diff --git a/src/datetime.rs b/src/datetime.rs
index 074b973..1e53753 100644
--- a/src/datetime.rs
+++ b/src/datetime.rs
@@ -575,8 +575,8 @@ impl<Tz: TimeZone, Tz2: TimeZone> PartialEq<DateTime<Tz2>> for DateTime<Tz> {
 impl<Tz: TimeZone> Eq for DateTime<Tz> {
 }
 
-impl<Tz: TimeZone> PartialOrd for DateTime<Tz> {
-    fn partial_cmp(&self, other: &DateTime<Tz>) -> Option<Ordering> {
+impl<Tz: TimeZone, Tz2: TimeZone> PartialOrd<DateTime<Tz2>> for DateTime<Tz> {
+    fn partial_cmp(&self, other: &DateTime<Tz2>) -> Option<Ordering> {
         self.datetime.partial_cmp(&other.datetime)
     }
 }
@@ -2032,6 +2032,9 @@ mod tests {
         assert_eq!(d.date(), tz.ymd(2017, 8, 9));
         assert_eq!(d.date().naive_local(), NaiveDate::from_ymd(2017, 8, 9));
         assert_eq!(d.date().and_time(d.time()), Some(d));
+
+        let utc_d = Utc.ymd(2017, 8, 9).and_hms(12, 34, 56);
+        assert!(utc_d < d);
     }
 
     #[test]