diff --git a/CHANGELOG.md b/CHANGELOG.md
index 95f318584..7d5256600 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -67,6 +67,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Support pagination in emoji packs API (for packs and for files in pack)
 - Support for viewing instances favicons next to posts and accounts
 - Added Pleroma.Upload.Filter.Exiftool as an alternate EXIF stripping mechanism targeting GPS/location metadata.
+- "By approval" registrations mode.
 - Configuration: Added `:welcome` settings for the welcome message to newly registered users.
 
 <details>
diff --git a/config/config.exs b/config/config.exs
index 48fe7c669..4b91a58b7 100644
--- a/config/config.exs
+++ b/config/config.exs
@@ -205,6 +205,7 @@
   registrations_open: true,
   invites_enabled: false,
   account_activation_required: false,
+  account_approval_required: false,
   federating: true,
   federation_incoming_replies_max_depth: 100,
   federation_reachability_timeout_days: 7,
@@ -237,6 +238,7 @@
   max_remote_account_fields: 20,
   account_field_name_length: 512,
   account_field_value_length: 2048,
+  registration_reason_length: 500,
   external_user_synchronization: true,
   extended_nickname_format: true,
   cleanup_attachments: false,
diff --git a/config/description.exs b/config/description.exs
index 91261c1e1..30a503696 100644
--- a/config/description.exs
+++ b/config/description.exs
@@ -661,6 +661,11 @@
         type: :boolean,
         description: "Require users to confirm their emails before signing in"
       },
+      %{
+        key: :account_approval_required,
+        type: :boolean,
+        description: "Require users to be manually approved by an admin before signing in"
+      },
       %{
         key: :federating,
         type: :boolean,
@@ -874,6 +879,14 @@
           2048
         ]
       },
+      %{
+        key: :registration_reason_length,
+        type: :integer,
+        description: "Maximum registration reason length. Default: 500.",
+        suggestions: [
+          500
+        ]
+      },
       %{
         key: :external_user_synchronization,
         type: :boolean,
diff --git a/docs/API/admin_api.md b/docs/API/admin_api.md
index baf895d90..4b143e4ee 100644
--- a/docs/API/admin_api.md
+++ b/docs/API/admin_api.md
@@ -19,6 +19,7 @@ Configuration options:
     - `local`: only local users
     - `external`: only external users
     - `active`: only active users
+    - `need_approval`: only unapproved users
     - `deactivated`: only deactivated users
     - `is_admin`: users with admin role
     - `is_moderator`: users with moderator role
@@ -46,7 +47,10 @@ Configuration options:
       "local": bool,
       "tags": array,
       "avatar": string,
-      "display_name": string
+      "display_name": string,
+      "confirmation_pending": bool,
+      "approval_pending": bool,
+      "registration_reason": string,
     },
     ...
   ]
@@ -242,6 +246,24 @@ Note: Available `:permission_group` is currently moderator and admin. 404 is ret
 }
 ```
 
+## `PATCH /api/pleroma/admin/users/approve`
+
+### Approve user
+
+- Params:
+  - `nicknames`: nicknames array
+- Response:
+
+```json
+{
+  users: [
+    {
+      // user object
+    }
+  ]
+}
+```
+
 ## `GET /api/pleroma/admin/users/:nickname_or_id`
 
 ### Retrive the details of a user
diff --git a/docs/configuration/cheatsheet.md b/docs/configuration/cheatsheet.md
index 2a25a024a..d6a9276ee 100644
--- a/docs/configuration/cheatsheet.md
+++ b/docs/configuration/cheatsheet.md
@@ -33,6 +33,7 @@ To add configuration to your config file, you can copy it from the base config.
 * `registrations_open`: Enable registrations for anyone, invitations can be enabled when false.
 * `invites_enabled`: Enable user invitations for admins (depends on `registrations_open: false`).
 * `account_activation_required`: Require users to confirm their emails before signing in.
+* `account_approval_required`: Require users to be manually approved by an admin before signing in.
 * `federating`: Enable federation with other instances.
 * `federation_incoming_replies_max_depth`: Max. depth of reply-to activities fetching on incoming federation, to prevent out-of-memory situations while fetching very long threads. If set to `nil`, threads of any depth will be fetched. Lower this value if you experience out-of-memory crashes.
 * `federation_reachability_timeout_days`: Timeout (in days) of each external federation target being unreachable prior to pausing federating to it.
@@ -58,6 +59,7 @@ To add configuration to your config file, you can copy it from the base config.
 * `max_remote_account_fields`: The maximum number of custom fields in the remote user profile (default: `20`).
 * `account_field_name_length`: An account field name maximum length (default: `512`).
 * `account_field_value_length`: An account field value maximum length (default: `2048`).
+* `registration_reason_length`: Maximum registration reason length (default: `500`).
 * `external_user_synchronization`: Enabling following/followers counters synchronization for external users.
 * `cleanup_attachments`: Remove attachments along with statuses. Does not affect duplicate files and attachments without status. Enabling this will increase load to database when deleting statuses on larger instances.
 
diff --git a/lib/pleroma/emails/admin_email.ex b/lib/pleroma/emails/admin_email.ex
index aa0b2a66b..c27ad1065 100644
--- a/lib/pleroma/emails/admin_email.ex
+++ b/lib/pleroma/emails/admin_email.ex
@@ -8,6 +8,7 @@ defmodule Pleroma.Emails.AdminEmail do
   import Swoosh.Email
 
   alias Pleroma.Config
+  alias Pleroma.HTML
   alias Pleroma.Web.Router.Helpers
 
   defp instance_config, do: Config.get(:instance)
@@ -82,4 +83,18 @@ def report(to, reporter, account, statuses, comment) do
     |> subject("#{instance_name()} Report")
     |> html_body(html_body)
   end
+
+  def new_unapproved_registration(to, account) do
+    html_body = """
+    <p>New account for review: <a href="#{user_url(account)}">@#{account.nickname}</a></p>
+    <blockquote>#{HTML.strip_tags(account.registration_reason)}</blockquote>
+    <a href="#{Pleroma.Web.base_url()}/pleroma/admin">Visit AdminFE</a>
+    """
+
+    new()
+    |> to({to.name, to.email})
+    |> from({instance_name(), instance_notify_email()})
+    |> subject("New account up for review on #{instance_name()} (@#{account.nickname})")
+    |> html_body(html_body)
+  end
 end
diff --git a/lib/pleroma/moderation_log.ex b/lib/pleroma/moderation_log.ex
index 7aacd9d80..31c9afe2a 100644
--- a/lib/pleroma/moderation_log.ex
+++ b/lib/pleroma/moderation_log.ex
@@ -409,6 +409,17 @@ def get_log_entry_message(%ModerationLog{
     "@#{actor_nickname} deactivated users: #{users_to_nicknames_string(users)}"
   end
 
+  @spec get_log_entry_message(ModerationLog) :: String.t()
+  def get_log_entry_message(%ModerationLog{
+        data: %{
+          "actor" => %{"nickname" => actor_nickname},
+          "action" => "approve",
+          "subject" => users
+        }
+      }) do
+    "@#{actor_nickname} approved users: #{users_to_nicknames_string(users)}"
+  end
+
   @spec get_log_entry_message(ModerationLog) :: String.t()
   def get_log_entry_message(%ModerationLog{
         data: %{
diff --git a/lib/pleroma/user.ex b/lib/pleroma/user.ex
index ed1db04c9..dcf6ebee2 100644
--- a/lib/pleroma/user.ex
+++ b/lib/pleroma/user.ex
@@ -42,7 +42,12 @@ defmodule Pleroma.User do
   require Logger
 
   @type t :: %__MODULE__{}
-  @type account_status :: :active | :deactivated | :password_reset_pending | :confirmation_pending
+  @type account_status ::
+          :active
+          | :deactivated
+          | :password_reset_pending
+          | :confirmation_pending
+          | :approval_pending
   @primary_key {:id, FlakeId.Ecto.CompatType, autogenerate: true}
 
   # credo:disable-for-next-line Credo.Check.Readability.MaxLineLength
@@ -106,6 +111,8 @@ defmodule Pleroma.User do
     field(:locked, :boolean, default: false)
     field(:confirmation_pending, :boolean, default: false)
     field(:password_reset_pending, :boolean, default: false)
+    field(:approval_pending, :boolean, default: false)
+    field(:registration_reason, :string, default: nil)
     field(:confirmation_token, :string, default: nil)
     field(:default_scope, :string, default: "public")
     field(:domain_blocks, {:array, :string}, default: [])
@@ -262,6 +269,7 @@ def binary_id(%User{} = user), do: binary_id(user.id)
   @spec account_status(User.t()) :: account_status()
   def account_status(%User{deactivated: true}), do: :deactivated
   def account_status(%User{password_reset_pending: true}), do: :password_reset_pending
+  def account_status(%User{approval_pending: true}), do: :approval_pending
 
   def account_status(%User{confirmation_pending: true}) do
     if Config.get([:instance, :account_activation_required]) do
@@ -633,6 +641,7 @@ def force_password_reset(user), do: update_password_reset_pending(user, true)
   def register_changeset(struct, params \\ %{}, opts \\ []) do
     bio_limit = Config.get([:instance, :user_bio_length], 5000)
     name_limit = Config.get([:instance, :user_name_length], 100)
+    reason_limit = Config.get([:instance, :registration_reason_length], 500)
     params = Map.put_new(params, :accepts_chat_messages, true)
 
     need_confirmation? =
@@ -642,8 +651,16 @@ def register_changeset(struct, params \\ %{}, opts \\ []) do
         opts[:need_confirmation]
       end
 
+    need_approval? =
+      if is_nil(opts[:need_approval]) do
+        Config.get([:instance, :account_approval_required])
+      else
+        opts[:need_approval]
+      end
+
     struct
     |> confirmation_changeset(need_confirmation: need_confirmation?)
+    |> approval_changeset(need_approval: need_approval?)
     |> cast(params, [
       :bio,
       :raw_bio,
@@ -653,7 +670,8 @@ def register_changeset(struct, params \\ %{}, opts \\ []) do
       :password,
       :password_confirmation,
       :emoji,
-      :accepts_chat_messages
+      :accepts_chat_messages,
+      :registration_reason
     ])
     |> validate_required([:name, :nickname, :password, :password_confirmation])
     |> validate_confirmation(:password)
@@ -664,6 +682,7 @@ def register_changeset(struct, params \\ %{}, opts \\ []) do
     |> validate_format(:email, @email_regex)
     |> validate_length(:bio, max: bio_limit)
     |> validate_length(:name, min: 1, max: name_limit)
+    |> validate_length(:registration_reason, max: reason_limit)
     |> maybe_validate_required_email(opts[:external])
     |> put_password_hash
     |> put_ap_id()
@@ -1494,6 +1513,19 @@ def deactivate(%User{} = user, status) do
     end
   end
 
+  def approve(users) when is_list(users) do
+    Repo.transaction(fn ->
+      Enum.map(users, fn user ->
+        with {:ok, user} <- approve(user), do: user
+      end)
+    end)
+  end
+
+  def approve(%User{} = user) do
+    change(user, approval_pending: false)
+    |> update_and_set_cache()
+  end
+
   def update_notification_settings(%User{} = user, settings) do
     user
     |> cast(%{notification_settings: settings}, [])
@@ -1520,12 +1552,17 @@ defp delete_or_deactivate(%User{local: false} = user), do: delete_and_invalidate
   defp delete_or_deactivate(%User{local: true} = user) do
     status = account_status(user)
 
-    if status == :confirmation_pending do
-      delete_and_invalidate_cache(user)
-    else
-      user
-      |> change(%{deactivated: true, email: nil})
-      |> update_and_set_cache()
+    case status do
+      :confirmation_pending ->
+        delete_and_invalidate_cache(user)
+
+      :approval_pending ->
+        delete_and_invalidate_cache(user)
+
+      _ ->
+        user
+        |> change(%{deactivated: true, email: nil})
+        |> update_and_set_cache()
     end
   end
 
@@ -2178,6 +2215,12 @@ def confirmation_changeset(user, need_confirmation: need_confirmation?) do
     cast(user, params, [:confirmation_pending, :confirmation_token])
   end
 
+  @spec approval_changeset(User.t(), keyword()) :: Changeset.t()
+  def approval_changeset(user, need_approval: need_approval?) do
+    params = if need_approval?, do: %{approval_pending: true}, else: %{approval_pending: false}
+    cast(user, params, [:approval_pending])
+  end
+
   def add_pinnned_activity(user, %Pleroma.Activity{id: id}) do
     if id not in user.pinned_activities do
       max_pinned_statuses = Config.get([:instance, :max_pinned_statuses], 0)
diff --git a/lib/pleroma/user/query.ex b/lib/pleroma/user/query.ex
index 66ffe9090..45553cb6c 100644
--- a/lib/pleroma/user/query.ex
+++ b/lib/pleroma/user/query.ex
@@ -42,6 +42,7 @@ defmodule Pleroma.User.Query do
             external: boolean(),
             active: boolean(),
             deactivated: boolean(),
+            need_approval: boolean(),
             is_admin: boolean(),
             is_moderator: boolean(),
             super_users: boolean(),
@@ -146,6 +147,10 @@ defp compose_query({:deactivated, true}, query) do
     |> where([u], not is_nil(u.nickname))
   end
 
+  defp compose_query({:need_approval, _}, query) do
+    where(query, [u], u.approval_pending)
+  end
+
   defp compose_query({:followers, %User{id: id}}, query) do
     query
     |> where([u], u.id != ^id)
diff --git a/lib/pleroma/web/admin_api/controllers/admin_api_controller.ex b/lib/pleroma/web/admin_api/controllers/admin_api_controller.ex
index 5101e28d6..aa2af1ab5 100644
--- a/lib/pleroma/web/admin_api/controllers/admin_api_controller.ex
+++ b/lib/pleroma/web/admin_api/controllers/admin_api_controller.ex
@@ -44,6 +44,7 @@ defmodule Pleroma.Web.AdminAPI.AdminAPIController do
            :user_toggle_activation,
            :user_activate,
            :user_deactivate,
+           :user_approve,
            :tag_users,
            :untag_users,
            :right_add,
@@ -303,6 +304,21 @@ def user_deactivate(%{assigns: %{user: admin}} = conn, %{"nicknames" => nickname
     |> render("index.json", %{users: Keyword.values(updated_users)})
   end
 
+  def user_approve(%{assigns: %{user: admin}} = conn, %{"nicknames" => nicknames}) do
+    users = Enum.map(nicknames, &User.get_cached_by_nickname/1)
+    {:ok, updated_users} = User.approve(users)
+
+    ModerationLog.insert_log(%{
+      actor: admin,
+      subject: users,
+      action: "approve"
+    })
+
+    conn
+    |> put_view(AccountView)
+    |> render("index.json", %{users: updated_users})
+  end
+
   def tag_users(%{assigns: %{user: admin}} = conn, %{"nicknames" => nicknames, "tags" => tags}) do
     with {:ok, _} <- User.tag(nicknames, tags) do
       ModerationLog.insert_log(%{
@@ -354,7 +370,7 @@ def list_users(conn, params) do
     end
   end
 
-  @filters ~w(local external active deactivated is_admin is_moderator)
+  @filters ~w(local external active deactivated need_approval is_admin is_moderator)
 
   @spec maybe_parse_filters(String.t()) :: %{required(String.t()) => true} | %{}
   defp maybe_parse_filters(filters) when is_nil(filters) or filters == "", do: %{}
diff --git a/lib/pleroma/web/admin_api/views/account_view.ex b/lib/pleroma/web/admin_api/views/account_view.ex
index 88fbb5315..333e72e42 100644
--- a/lib/pleroma/web/admin_api/views/account_view.ex
+++ b/lib/pleroma/web/admin_api/views/account_view.ex
@@ -77,7 +77,9 @@ def render("show.json", %{user: user}) do
       "roles" => User.roles(user),
       "tags" => user.tags || [],
       "confirmation_pending" => user.confirmation_pending,
-      "url" => user.uri || user.ap_id
+      "approval_pending" => user.approval_pending,
+      "url" => user.uri || user.ap_id,
+      "registration_reason" => user.registration_reason
     }
   end
 
diff --git a/lib/pleroma/web/mastodon_api/views/instance_view.ex b/lib/pleroma/web/mastodon_api/views/instance_view.ex
index cd3bc7f00..ea2d3aa9c 100644
--- a/lib/pleroma/web/mastodon_api/views/instance_view.ex
+++ b/lib/pleroma/web/mastodon_api/views/instance_view.ex
@@ -26,6 +26,7 @@ def render("show.json", _) do
       thumbnail: Keyword.get(instance, :instance_thumbnail),
       languages: ["en"],
       registrations: Keyword.get(instance, :registrations_open),
+      approval_required: Keyword.get(instance, :account_approval_required),
       # Extra (not present in Mastodon):
       max_toot_chars: Keyword.get(instance, :limit),
       poll_limits: Keyword.get(instance, :poll_limits),
diff --git a/lib/pleroma/web/oauth/oauth_controller.ex b/lib/pleroma/web/oauth/oauth_controller.ex
index 7683589cf..61fe81d33 100644
--- a/lib/pleroma/web/oauth/oauth_controller.ex
+++ b/lib/pleroma/web/oauth/oauth_controller.ex
@@ -337,6 +337,16 @@ defp handle_token_exchange_error(%Plug.Conn{} = conn, {:account_status, :confirm
     )
   end
 
+  defp handle_token_exchange_error(%Plug.Conn{} = conn, {:account_status, :approval_pending}) do
+    render_error(
+      conn,
+      :forbidden,
+      "Your account is awaiting approval.",
+      %{},
+      "awaiting_approval"
+    )
+  end
+
   defp handle_token_exchange_error(%Plug.Conn{} = conn, _error) do
     render_invalid_credentials_error(conn)
   end
diff --git a/lib/pleroma/web/router.ex b/lib/pleroma/web/router.ex
index 386308362..c6433cc53 100644
--- a/lib/pleroma/web/router.ex
+++ b/lib/pleroma/web/router.ex
@@ -138,6 +138,7 @@ defmodule Pleroma.Web.Router do
     patch("/users/:nickname/toggle_activation", AdminAPIController, :user_toggle_activation)
     patch("/users/activate", AdminAPIController, :user_activate)
     patch("/users/deactivate", AdminAPIController, :user_deactivate)
+    patch("/users/approve", AdminAPIController, :user_approve)
     put("/users/tag", AdminAPIController, :tag_users)
     delete("/users/tag", AdminAPIController, :untag_users)
 
diff --git a/lib/pleroma/web/twitter_api/twitter_api.ex b/lib/pleroma/web/twitter_api/twitter_api.ex
index 5cfb385ac..2294d9d0d 100644
--- a/lib/pleroma/web/twitter_api/twitter_api.ex
+++ b/lib/pleroma/web/twitter_api/twitter_api.ex
@@ -19,6 +19,7 @@ def register_user(params, opts \\ []) do
       |> Map.put(:nickname, params[:username])
       |> Map.put(:name, Map.get(params, :fullname, params[:username]))
       |> Map.put(:password_confirmation, params[:password])
+      |> Map.put(:registration_reason, params[:reason])
 
     if Pleroma.Config.get([:instance, :registrations_open]) do
       create_user(params, opts)
@@ -44,6 +45,7 @@ defp create_user(params, opts) do
 
     case User.register(changeset) do
       {:ok, user} ->
+        maybe_notify_admins(user)
         {:ok, user}
 
       {:error, changeset} ->
@@ -56,6 +58,18 @@ defp create_user(params, opts) do
     end
   end
 
+  defp maybe_notify_admins(%User{} = account) do
+    if Pleroma.Config.get([:instance, :account_approval_required]) do
+      User.all_superusers()
+      |> Enum.filter(fn user -> not is_nil(user.email) end)
+      |> Enum.each(fn superuser ->
+        superuser
+        |> Pleroma.Emails.AdminEmail.new_unapproved_registration(account)
+        |> Pleroma.Emails.Mailer.deliver_async()
+      end)
+    end
+  end
+
   def password_reset(nickname_or_email) do
     with true <- is_binary(nickname_or_email),
          %User{local: true, email: email} = user when is_binary(email) <-
diff --git a/priv/repo/migrations/20200712234852_add_approval_fields_to_users.exs b/priv/repo/migrations/20200712234852_add_approval_fields_to_users.exs
new file mode 100644
index 000000000..43f741a5b
--- /dev/null
+++ b/priv/repo/migrations/20200712234852_add_approval_fields_to_users.exs
@@ -0,0 +1,10 @@
+defmodule Pleroma.Repo.Migrations.AddApprovalFieldsToUsers do
+  use Ecto.Migration
+
+  def change do
+    alter table(:users) do
+      add(:approval_pending, :boolean)
+      add(:registration_reason, :text)
+    end
+  end
+end
diff --git a/test/emails/admin_email_test.exs b/test/emails/admin_email_test.exs
index 9082ae5a7..e24231e27 100644
--- a/test/emails/admin_email_test.exs
+++ b/test/emails/admin_email_test.exs
@@ -46,4 +46,24 @@ test "it works when the reporter is a remote user without email" do
     assert res.to == [{to_user.name, to_user.email}]
     assert res.from == {config[:name], config[:notify_email]}
   end
+
+  test "new unapproved registration email" do
+    config = Pleroma.Config.get(:instance)
+    to_user = insert(:user)
+    account = insert(:user, registration_reason: "Plz let me in")
+
+    res = AdminEmail.new_unapproved_registration(to_user, account)
+
+    account_url = Helpers.user_feed_url(Pleroma.Web.Endpoint, :feed_redirect, account.id)
+
+    assert res.to == [{to_user.name, to_user.email}]
+    assert res.from == {config[:name], config[:notify_email]}
+    assert res.subject == "New account up for review on #{config[:name]} (@#{account.nickname})"
+
+    assert res.html_body == """
+           <p>New account for review: <a href="#{account_url}">@#{account.nickname}</a></p>
+           <blockquote>Plz let me in</blockquote>
+           <a href="http://localhost:4001/pleroma/admin">Visit AdminFE</a>
+           """
+  end
 end
diff --git a/test/user_test.exs b/test/user_test.exs
index d087e9101..624baf8ad 100644
--- a/test/user_test.exs
+++ b/test/user_test.exs
@@ -543,6 +543,46 @@ test "it creates confirmed user if :confirmed option is given" do
     end
   end
 
+  describe "user registration, with :account_approval_required" do
+    @full_user_data %{
+      bio: "A guy",
+      name: "my name",
+      nickname: "nick",
+      password: "test",
+      password_confirmation: "test",
+      email: "email@example.com",
+      registration_reason: "I'm a cool guy :)"
+    }
+    setup do: clear_config([:instance, :account_approval_required], true)
+
+    test "it creates unapproved user" do
+      changeset = User.register_changeset(%User{}, @full_user_data)
+      assert changeset.valid?
+
+      {:ok, user} = Repo.insert(changeset)
+
+      assert user.approval_pending
+      assert user.registration_reason == "I'm a cool guy :)"
+    end
+
+    test "it restricts length of registration reason" do
+      reason_limit = Pleroma.Config.get([:instance, :registration_reason_length])
+
+      assert is_integer(reason_limit)
+
+      params =
+        @full_user_data
+        |> Map.put(
+          :registration_reason,
+          "Quia et nesciunt dolores numquam ipsam nisi sapiente soluta. Ullam repudiandae nisi quam porro officiis officiis ad. Consequatur animi velit ex quia. Odit voluptatem perferendis quia ut nisi. Dignissimos sit soluta atque aliquid dolorem ut dolorum ut. Labore voluptates iste iusto amet voluptatum earum. Ad fugit illum nam eos ut nemo. Pariatur ea fuga non aspernatur. Dignissimos debitis officia corporis est nisi ab et. Atque itaque alias eius voluptas minus. Accusamus numquam tempore occaecati in."
+        )
+
+      changeset = User.register_changeset(%User{}, params)
+
+      refute changeset.valid?
+    end
+  end
+
   describe "get_or_fetch/1" do
     test "gets an existing user by nickname" do
       user = insert(:user)
@@ -1208,6 +1248,31 @@ test "hide a user's statuses from timelines and notifications" do
     end
   end
 
+  describe "approve" do
+    test "approves a user" do
+      user = insert(:user, approval_pending: true)
+      assert true == user.approval_pending
+      {:ok, user} = User.approve(user)
+      assert false == user.approval_pending
+    end
+
+    test "approves a list of users" do
+      unapproved_users = [
+        insert(:user, approval_pending: true),
+        insert(:user, approval_pending: true),
+        insert(:user, approval_pending: true)
+      ]
+
+      {:ok, users} = User.approve(unapproved_users)
+
+      assert Enum.count(users) == 3
+
+      Enum.each(users, fn user ->
+        assert false == user.approval_pending
+      end)
+    end
+  end
+
   describe "delete" do
     setup do
       {:ok, user} = insert(:user) |> User.set_cache()
@@ -1295,6 +1360,17 @@ test "deactivates user when activation is not required", %{user: user} do
     end
   end
 
+  test "delete/1 when approval is pending deletes the user" do
+    user = insert(:user, approval_pending: true)
+    {:ok, user: user}
+
+    {:ok, job} = User.delete(user)
+    {:ok, _} = ObanHelpers.perform(job)
+
+    refute User.get_cached_by_id(user.id)
+    refute User.get_by_id(user.id)
+  end
+
   test "get_public_key_for_ap_id fetches a user that's not in the db" do
     assert {:ok, _key} = User.get_public_key_for_ap_id("http://mastodon.example.org/users/admin")
   end
@@ -1369,6 +1445,14 @@ test "returns :deactivated for deactivated user" do
       user = insert(:user, local: true, confirmation_pending: false, deactivated: true)
       assert User.account_status(user) == :deactivated
     end
+
+    test "returns :approval_pending for unapproved user" do
+      user = insert(:user, local: true, approval_pending: true)
+      assert User.account_status(user) == :approval_pending
+
+      user = insert(:user, local: true, confirmation_pending: true, approval_pending: true)
+      assert User.account_status(user) == :approval_pending
+    end
   end
 
   describe "superuser?/1" do
diff --git a/test/web/admin_api/controllers/admin_api_controller_test.exs b/test/web/admin_api/controllers/admin_api_controller_test.exs
index 6082441ee..b5d5bd8c7 100644
--- a/test/web/admin_api/controllers/admin_api_controller_test.exs
+++ b/test/web/admin_api/controllers/admin_api_controller_test.exs
@@ -349,7 +349,9 @@ test "Show", %{conn: conn} do
         "avatar" => User.avatar_url(user) |> MediaProxy.url(),
         "display_name" => HTML.strip_tags(user.name || user.nickname),
         "confirmation_pending" => false,
-        "url" => user.ap_id
+        "approval_pending" => false,
+        "url" => user.ap_id,
+        "registration_reason" => nil
       }
 
       assert expected == json_response(conn, 200)
@@ -613,6 +615,8 @@ test "/api/pleroma/admin/users/:nickname/password_reset", %{conn: conn} do
   describe "GET /api/pleroma/admin/users" do
     test "renders users array for the first page", %{conn: conn, admin: admin} do
       user = insert(:user, local: false, tags: ["foo", "bar"])
+      user2 = insert(:user, approval_pending: true, registration_reason: "I'm a chill dude")
+
       conn = get(conn, "/api/pleroma/admin/users?page=1")
 
       users =
@@ -627,7 +631,9 @@ test "renders users array for the first page", %{conn: conn, admin: admin} do
             "avatar" => User.avatar_url(admin) |> MediaProxy.url(),
             "display_name" => HTML.strip_tags(admin.name || admin.nickname),
             "confirmation_pending" => false,
-            "url" => admin.ap_id
+            "approval_pending" => false,
+            "url" => admin.ap_id,
+            "registration_reason" => nil
           },
           %{
             "deactivated" => user.deactivated,
@@ -639,13 +645,29 @@ test "renders users array for the first page", %{conn: conn, admin: admin} do
             "avatar" => User.avatar_url(user) |> MediaProxy.url(),
             "display_name" => HTML.strip_tags(user.name || user.nickname),
             "confirmation_pending" => false,
-            "url" => user.ap_id
+            "approval_pending" => false,
+            "url" => user.ap_id,
+            "registration_reason" => nil
+          },
+          %{
+            "deactivated" => user2.deactivated,
+            "id" => user2.id,
+            "nickname" => user2.nickname,
+            "roles" => %{"admin" => false, "moderator" => false},
+            "local" => true,
+            "tags" => [],
+            "avatar" => User.avatar_url(user2) |> MediaProxy.url(),
+            "display_name" => HTML.strip_tags(user2.name || user2.nickname),
+            "confirmation_pending" => false,
+            "approval_pending" => true,
+            "url" => user2.ap_id,
+            "registration_reason" => "I'm a chill dude"
           }
         ]
         |> Enum.sort_by(& &1["nickname"])
 
       assert json_response(conn, 200) == %{
-               "count" => 2,
+               "count" => 3,
                "page_size" => 50,
                "users" => users
              }
@@ -712,7 +734,9 @@ test "regular search", %{conn: conn} do
                    "avatar" => User.avatar_url(user) |> MediaProxy.url(),
                    "display_name" => HTML.strip_tags(user.name || user.nickname),
                    "confirmation_pending" => false,
-                   "url" => user.ap_id
+                   "approval_pending" => false,
+                   "url" => user.ap_id,
+                   "registration_reason" => nil
                  }
                ]
              }
@@ -738,7 +762,9 @@ test "search by domain", %{conn: conn} do
                    "avatar" => User.avatar_url(user) |> MediaProxy.url(),
                    "display_name" => HTML.strip_tags(user.name || user.nickname),
                    "confirmation_pending" => false,
-                   "url" => user.ap_id
+                   "approval_pending" => false,
+                   "url" => user.ap_id,
+                   "registration_reason" => nil
                  }
                ]
              }
@@ -764,7 +790,9 @@ test "search by full nickname", %{conn: conn} do
                    "avatar" => User.avatar_url(user) |> MediaProxy.url(),
                    "display_name" => HTML.strip_tags(user.name || user.nickname),
                    "confirmation_pending" => false,
-                   "url" => user.ap_id
+                   "approval_pending" => false,
+                   "url" => user.ap_id,
+                   "registration_reason" => nil
                  }
                ]
              }
@@ -790,7 +818,9 @@ test "search by display name", %{conn: conn} do
                    "avatar" => User.avatar_url(user) |> MediaProxy.url(),
                    "display_name" => HTML.strip_tags(user.name || user.nickname),
                    "confirmation_pending" => false,
-                   "url" => user.ap_id
+                   "approval_pending" => false,
+                   "url" => user.ap_id,
+                   "registration_reason" => nil
                  }
                ]
              }
@@ -816,7 +846,9 @@ test "search by email", %{conn: conn} do
                    "avatar" => User.avatar_url(user) |> MediaProxy.url(),
                    "display_name" => HTML.strip_tags(user.name || user.nickname),
                    "confirmation_pending" => false,
-                   "url" => user.ap_id
+                   "approval_pending" => false,
+                   "url" => user.ap_id,
+                   "registration_reason" => nil
                  }
                ]
              }
@@ -842,7 +874,9 @@ test "regular search with page size", %{conn: conn} do
                    "avatar" => User.avatar_url(user) |> MediaProxy.url(),
                    "display_name" => HTML.strip_tags(user.name || user.nickname),
                    "confirmation_pending" => false,
-                   "url" => user.ap_id
+                   "approval_pending" => false,
+                   "url" => user.ap_id,
+                   "registration_reason" => nil
                  }
                ]
              }
@@ -863,7 +897,9 @@ test "regular search with page size", %{conn: conn} do
                    "avatar" => User.avatar_url(user2) |> MediaProxy.url(),
                    "display_name" => HTML.strip_tags(user2.name || user2.nickname),
                    "confirmation_pending" => false,
-                   "url" => user2.ap_id
+                   "approval_pending" => false,
+                   "url" => user2.ap_id,
+                   "registration_reason" => nil
                  }
                ]
              }
@@ -896,7 +932,9 @@ test "only local users" do
                    "avatar" => User.avatar_url(user) |> MediaProxy.url(),
                    "display_name" => HTML.strip_tags(user.name || user.nickname),
                    "confirmation_pending" => false,
-                   "url" => user.ap_id
+                   "approval_pending" => false,
+                   "url" => user.ap_id,
+                   "registration_reason" => nil
                  }
                ]
              }
@@ -922,7 +960,9 @@ test "only local users with no query", %{conn: conn, admin: old_admin} do
             "avatar" => User.avatar_url(user) |> MediaProxy.url(),
             "display_name" => HTML.strip_tags(user.name || user.nickname),
             "confirmation_pending" => false,
-            "url" => user.ap_id
+            "approval_pending" => false,
+            "url" => user.ap_id,
+            "registration_reason" => nil
           },
           %{
             "deactivated" => admin.deactivated,
@@ -934,7 +974,9 @@ test "only local users with no query", %{conn: conn, admin: old_admin} do
             "avatar" => User.avatar_url(admin) |> MediaProxy.url(),
             "display_name" => HTML.strip_tags(admin.name || admin.nickname),
             "confirmation_pending" => false,
-            "url" => admin.ap_id
+            "approval_pending" => false,
+            "url" => admin.ap_id,
+            "registration_reason" => nil
           },
           %{
             "deactivated" => false,
@@ -946,7 +988,9 @@ test "only local users with no query", %{conn: conn, admin: old_admin} do
             "avatar" => User.avatar_url(old_admin) |> MediaProxy.url(),
             "display_name" => HTML.strip_tags(old_admin.name || old_admin.nickname),
             "confirmation_pending" => false,
-            "url" => old_admin.ap_id
+            "approval_pending" => false,
+            "url" => old_admin.ap_id,
+            "registration_reason" => nil
           }
         ]
         |> Enum.sort_by(& &1["nickname"])
@@ -958,6 +1002,44 @@ test "only local users with no query", %{conn: conn, admin: old_admin} do
              }
     end
 
+    test "only unapproved users", %{conn: conn} do
+      user =
+        insert(:user,
+          nickname: "sadboy",
+          approval_pending: true,
+          registration_reason: "Plz let me in!"
+        )
+
+      insert(:user, nickname: "happyboy", approval_pending: false)
+
+      conn = get(conn, "/api/pleroma/admin/users?filters=need_approval")
+
+      users =
+        [
+          %{
+            "deactivated" => user.deactivated,
+            "id" => user.id,
+            "nickname" => user.nickname,
+            "roles" => %{"admin" => false, "moderator" => false},
+            "local" => true,
+            "tags" => [],
+            "avatar" => User.avatar_url(user) |> MediaProxy.url(),
+            "display_name" => HTML.strip_tags(user.name || user.nickname),
+            "confirmation_pending" => false,
+            "approval_pending" => true,
+            "url" => user.ap_id,
+            "registration_reason" => "Plz let me in!"
+          }
+        ]
+        |> Enum.sort_by(& &1["nickname"])
+
+      assert json_response(conn, 200) == %{
+               "count" => 1,
+               "page_size" => 50,
+               "users" => users
+             }
+    end
+
     test "load only admins", %{conn: conn, admin: admin} do
       second_admin = insert(:user, is_admin: true)
       insert(:user)
@@ -977,7 +1059,9 @@ test "load only admins", %{conn: conn, admin: admin} do
             "avatar" => User.avatar_url(admin) |> MediaProxy.url(),
             "display_name" => HTML.strip_tags(admin.name || admin.nickname),
             "confirmation_pending" => false,
-            "url" => admin.ap_id
+            "approval_pending" => false,
+            "url" => admin.ap_id,
+            "registration_reason" => nil
           },
           %{
             "deactivated" => false,
@@ -989,7 +1073,9 @@ test "load only admins", %{conn: conn, admin: admin} do
             "avatar" => User.avatar_url(second_admin) |> MediaProxy.url(),
             "display_name" => HTML.strip_tags(second_admin.name || second_admin.nickname),
             "confirmation_pending" => false,
-            "url" => second_admin.ap_id
+            "approval_pending" => false,
+            "url" => second_admin.ap_id,
+            "registration_reason" => nil
           }
         ]
         |> Enum.sort_by(& &1["nickname"])
@@ -1022,7 +1108,9 @@ test "load only moderators", %{conn: conn} do
                    "avatar" => User.avatar_url(moderator) |> MediaProxy.url(),
                    "display_name" => HTML.strip_tags(moderator.name || moderator.nickname),
                    "confirmation_pending" => false,
-                   "url" => moderator.ap_id
+                   "approval_pending" => false,
+                   "url" => moderator.ap_id,
+                   "registration_reason" => nil
                  }
                ]
              }
@@ -1048,7 +1136,9 @@ test "load users with tags list", %{conn: conn} do
             "avatar" => User.avatar_url(user1) |> MediaProxy.url(),
             "display_name" => HTML.strip_tags(user1.name || user1.nickname),
             "confirmation_pending" => false,
-            "url" => user1.ap_id
+            "approval_pending" => false,
+            "url" => user1.ap_id,
+            "registration_reason" => nil
           },
           %{
             "deactivated" => false,
@@ -1060,7 +1150,9 @@ test "load users with tags list", %{conn: conn} do
             "avatar" => User.avatar_url(user2) |> MediaProxy.url(),
             "display_name" => HTML.strip_tags(user2.name || user2.nickname),
             "confirmation_pending" => false,
-            "url" => user2.ap_id
+            "approval_pending" => false,
+            "url" => user2.ap_id,
+            "registration_reason" => nil
           }
         ]
         |> Enum.sort_by(& &1["nickname"])
@@ -1100,7 +1192,9 @@ test "it works with multiple filters" do
                    "avatar" => User.avatar_url(user) |> MediaProxy.url(),
                    "display_name" => HTML.strip_tags(user.name || user.nickname),
                    "confirmation_pending" => false,
-                   "url" => user.ap_id
+                   "approval_pending" => false,
+                   "url" => user.ap_id,
+                   "registration_reason" => nil
                  }
                ]
              }
@@ -1125,7 +1219,9 @@ test "it omits relay user", %{admin: admin, conn: conn} do
                    "avatar" => User.avatar_url(admin) |> MediaProxy.url(),
                    "display_name" => HTML.strip_tags(admin.name || admin.nickname),
                    "confirmation_pending" => false,
-                   "url" => admin.ap_id
+                   "approval_pending" => false,
+                   "url" => admin.ap_id,
+                   "registration_reason" => nil
                  }
                ]
              }
@@ -1172,6 +1268,26 @@ test "PATCH /api/pleroma/admin/users/deactivate", %{admin: admin, conn: conn} do
              "@#{admin.nickname} deactivated users: @#{user_one.nickname}, @#{user_two.nickname}"
   end
 
+  test "PATCH /api/pleroma/admin/users/approve", %{admin: admin, conn: conn} do
+    user_one = insert(:user, approval_pending: true)
+    user_two = insert(:user, approval_pending: true)
+
+    conn =
+      patch(
+        conn,
+        "/api/pleroma/admin/users/approve",
+        %{nicknames: [user_one.nickname, user_two.nickname]}
+      )
+
+    response = json_response(conn, 200)
+    assert Enum.map(response["users"], & &1["approval_pending"]) == [false, false]
+
+    log_entry = Repo.one(ModerationLog)
+
+    assert ModerationLog.get_log_entry_message(log_entry) ==
+             "@#{admin.nickname} approved users: @#{user_one.nickname}, @#{user_two.nickname}"
+  end
+
   test "PATCH /api/pleroma/admin/users/:nickname/toggle_activation", %{admin: admin, conn: conn} do
     user = insert(:user)
 
@@ -1188,7 +1304,9 @@ test "PATCH /api/pleroma/admin/users/:nickname/toggle_activation", %{admin: admi
                "avatar" => User.avatar_url(user) |> MediaProxy.url(),
                "display_name" => HTML.strip_tags(user.name || user.nickname),
                "confirmation_pending" => false,
-               "url" => user.ap_id
+               "approval_pending" => false,
+               "url" => user.ap_id,
+               "registration_reason" => nil
              }
 
     log_entry = Repo.one(ModerationLog)
diff --git a/test/web/admin_api/search_test.exs b/test/web/admin_api/search_test.exs
index e0e3d4153..b974cedd5 100644
--- a/test/web/admin_api/search_test.exs
+++ b/test/web/admin_api/search_test.exs
@@ -166,5 +166,16 @@ test "it returns user by email" do
       assert total == 3
       assert count == 1
     end
+
+    test "it returns unapproved user" do
+      unapproved = insert(:user, approval_pending: true)
+      insert(:user)
+      insert(:user)
+
+      {:ok, _results, total} = Search.user()
+      {:ok, [^unapproved], count} = Search.user(%{need_approval: true})
+      assert total == 3
+      assert count == 1
+    end
   end
 end
diff --git a/test/web/mastodon_api/controllers/account_controller_test.exs b/test/web/mastodon_api/controllers/account_controller_test.exs
index c304487ea..e6b283aab 100644
--- a/test/web/mastodon_api/controllers/account_controller_test.exs
+++ b/test/web/mastodon_api/controllers/account_controller_test.exs
@@ -904,6 +904,7 @@ test "blocking / unblocking a user" do
     end
 
     setup do: clear_config([:instance, :account_activation_required])
+    setup do: clear_config([:instance, :account_approval_required])
 
     test "Account registration via Application", %{conn: conn} do
       conn =
@@ -968,6 +969,75 @@ test "Account registration via Application", %{conn: conn} do
       assert token_from_db.user.confirmation_pending
     end
 
+    test "Account registration via app with account_approval_required", %{conn: conn} do
+      Pleroma.Config.put([:instance, :account_approval_required], true)
+
+      conn =
+        conn
+        |> put_req_header("content-type", "application/json")
+        |> post("/api/v1/apps", %{
+          client_name: "client_name",
+          redirect_uris: "urn:ietf:wg:oauth:2.0:oob",
+          scopes: "read, write, follow"
+        })
+
+      assert %{
+               "client_id" => client_id,
+               "client_secret" => client_secret,
+               "id" => _,
+               "name" => "client_name",
+               "redirect_uri" => "urn:ietf:wg:oauth:2.0:oob",
+               "vapid_key" => _,
+               "website" => nil
+             } = json_response_and_validate_schema(conn, 200)
+
+      conn =
+        post(conn, "/oauth/token", %{
+          grant_type: "client_credentials",
+          client_id: client_id,
+          client_secret: client_secret
+        })
+
+      assert %{"access_token" => token, "refresh_token" => refresh, "scope" => scope} =
+               json_response(conn, 200)
+
+      assert token
+      token_from_db = Repo.get_by(Token, token: token)
+      assert token_from_db
+      assert refresh
+      assert scope == "read write follow"
+
+      conn =
+        build_conn()
+        |> put_req_header("content-type", "multipart/form-data")
+        |> put_req_header("authorization", "Bearer " <> token)
+        |> post("/api/v1/accounts", %{
+          username: "lain",
+          email: "lain@example.org",
+          password: "PlzDontHackLain",
+          bio: "Test Bio",
+          agreement: true,
+          reason: "I'm a cool dude, bro"
+        })
+
+      %{
+        "access_token" => token,
+        "created_at" => _created_at,
+        "scope" => ^scope,
+        "token_type" => "Bearer"
+      } = json_response_and_validate_schema(conn, 200)
+
+      token_from_db = Repo.get_by(Token, token: token)
+      assert token_from_db
+      token_from_db = Repo.preload(token_from_db, :user)
+      assert token_from_db.user
+
+      assert token_from_db.user.confirmation_pending
+      assert token_from_db.user.approval_pending
+
+      assert token_from_db.user.registration_reason == "I'm a cool dude, bro"
+    end
+
     test "returns error when user already registred", %{conn: conn, valid_params: valid_params} do
       _user = insert(:user, email: "lain@example.org")
       app_token = insert(:oauth_token, user: nil)
diff --git a/test/web/mastodon_api/controllers/instance_controller_test.exs b/test/web/mastodon_api/controllers/instance_controller_test.exs
index cc880d82c..6a9ccd979 100644
--- a/test/web/mastodon_api/controllers/instance_controller_test.exs
+++ b/test/web/mastodon_api/controllers/instance_controller_test.exs
@@ -27,6 +27,7 @@ test "get instance information", %{conn: conn} do
              "thumbnail" => _,
              "languages" => _,
              "registrations" => _,
+             "approval_required" => _,
              "poll_limits" => _,
              "upload_limit" => _,
              "avatar_upload_limit" => _,
diff --git a/test/web/oauth/oauth_controller_test.exs b/test/web/oauth/oauth_controller_test.exs
index d389e4ce0..1200126b8 100644
--- a/test/web/oauth/oauth_controller_test.exs
+++ b/test/web/oauth/oauth_controller_test.exs
@@ -19,7 +19,10 @@ defmodule Pleroma.Web.OAuth.OAuthControllerTest do
     key: "_test",
     signing_salt: "cooldude"
   ]
-  setup do: clear_config([:instance, :account_activation_required])
+  setup do
+    clear_config([:instance, :account_activation_required])
+    clear_config([:instance, :account_approval_required])
+  end
 
   describe "in OAuth consumer mode, " do
     setup do
@@ -995,6 +998,30 @@ test "rejects token exchange for user with confirmation_pending set to true" do
              }
     end
 
+    test "rejects token exchange for valid credentials belonging to an unapproved user" do
+      password = "testpassword"
+
+      user = insert(:user, password_hash: Pbkdf2.hash_pwd_salt(password), approval_pending: true)
+
+      refute Pleroma.User.account_status(user) == :active
+
+      app = insert(:oauth_app)
+
+      conn =
+        build_conn()
+        |> post("/oauth/token", %{
+          "grant_type" => "password",
+          "username" => user.nickname,
+          "password" => password,
+          "client_id" => app.client_id,
+          "client_secret" => app.client_secret
+        })
+
+      assert resp = json_response(conn, 403)
+      assert %{"error" => _} = resp
+      refute Map.has_key?(resp, "access_token")
+    end
+
     test "rejects an invalid authorization code" do
       app = insert(:oauth_app)
 
diff --git a/test/web/twitter_api/twitter_api_test.exs b/test/web/twitter_api/twitter_api_test.exs
index 5bb2d8d89..20a45cb6f 100644
--- a/test/web/twitter_api/twitter_api_test.exs
+++ b/test/web/twitter_api/twitter_api_test.exs
@@ -4,7 +4,7 @@
 
 defmodule Pleroma.Web.TwitterAPI.TwitterAPITest do
   use Pleroma.DataCase
-
+  import Pleroma.Factory
   alias Pleroma.Repo
   alias Pleroma.Tests.ObanHelpers
   alias Pleroma.User
@@ -79,6 +79,42 @@ test "it sends confirmation email if :account_activation_required is specified i
     )
   end
 
+  test "it sends an admin email if :account_approval_required is specified in instance config" do
+    admin = insert(:user, is_admin: true)
+    setting = Pleroma.Config.get([:instance, :account_approval_required])
+
+    unless setting do
+      Pleroma.Config.put([:instance, :account_approval_required], true)
+      on_exit(fn -> Pleroma.Config.put([:instance, :account_approval_required], setting) end)
+    end
+
+    data = %{
+      :username => "lain",
+      :email => "lain@wired.jp",
+      :fullname => "lain iwakura",
+      :bio => "",
+      :password => "bear",
+      :confirm => "bear",
+      :reason => "I love anime"
+    }
+
+    {:ok, user} = TwitterAPI.register_user(data)
+    ObanHelpers.perform_all()
+
+    assert user.approval_pending
+
+    email = Pleroma.Emails.AdminEmail.new_unapproved_registration(admin, user)
+
+    notify_email = Pleroma.Config.get([:instance, :notify_email])
+    instance_name = Pleroma.Config.get([:instance, :name])
+
+    Swoosh.TestAssertions.assert_email_sent(
+      from: {instance_name, notify_email},
+      to: {admin.name, admin.email},
+      html_body: email.html_body
+    )
+  end
+
   test "it registers a new user and parses mentions in the bio" do
     data1 = %{
       :username => "john",