diff --git a/zerver/lib/create_user.py b/zerver/lib/create_user.py
index 3f5cca8781..cb0b8d0f0b 100644
--- a/zerver/lib/create_user.py
+++ b/zerver/lib/create_user.py
@@ -14,6 +14,19 @@ def random_api_key() -> str:
     altchars = ''.join([choices[ord(os.urandom(1)) % 62] for _ in range(2)]).encode("utf-8")
     return base64.b64encode(os.urandom(24), altchars=altchars).decode("utf-8")
 
+def copy_user_settings(source_profile: UserProfile,
+                       target_profile: UserProfile) -> UserProfile:
+    """Warning: Does not save, to avoid extra database queries"""
+    for settings_name in UserProfile.property_types:
+        value = getattr(source_profile, settings_name)
+        setattr(target_profile, settings_name, value)
+
+    for settings_name in UserProfile.notification_setting_types:
+        value = getattr(source_profile, settings_name)
+        setattr(target_profile, settings_name, value)
+
+    return target_profile
+
 # create_user_profile is based on Django's User.objects.create_user,
 # except that we don't save to the database so it can used in
 # bulk_creates
diff --git a/zerver/tests/test_users.py b/zerver/tests/test_users.py
index a25f580110..8f46b4e48a 100644
--- a/zerver/tests/test_users.py
+++ b/zerver/tests/test_users.py
@@ -35,6 +35,7 @@ from zerver.lib.actions import (
     do_change_is_admin,
     do_create_user,
 )
+from zerver.lib.create_user import copy_user_settings
 from zerver.lib.topic_mutes import add_topic_mute
 from zerver.lib.stream_topic import StreamTopicTarget
 from zerver.lib.users import user_ids_to_users
@@ -369,6 +370,46 @@ class UserProfileTest(ZulipTestCase):
         self.assertIsNone(get_source_profile("iago@zulip.com", "ZULIP"))
         self.assertIsNone(get_source_profile("iago@zulip.com", "lear"))
 
+    def test_copy_user_settings(self) -> None:
+        iago = self.example_user("iago")
+        cordelia = self.example_user("cordelia")
+        hamlet = self.example_user("hamlet")
+
+        cordelia.default_language = "de"
+        cordelia.emojiset = "apple"
+        cordelia.timezone = "America/Phoenix"
+        cordelia.night_mode = True
+        cordelia.enable_offline_email_notifications = False
+        cordelia.enable_stream_push_notifications = True
+        cordelia.save()
+
+        cordelia = copy_user_settings(cordelia, iago)
+
+        # We verify that cordelia and iago match, but hamlet has the defaults.
+        self.assertEqual(iago.default_language, "de")
+        self.assertEqual(cordelia.default_language, "de")
+        self.assertEqual(hamlet.default_language, "en")
+
+        self.assertEqual(iago.emojiset, "apple")
+        self.assertEqual(cordelia.emojiset, "apple")
+        self.assertEqual(hamlet.emojiset, "google")
+
+        self.assertEqual(iago.timezone, "America/Phoenix")
+        self.assertEqual(cordelia.timezone, "America/Phoenix")
+        self.assertEqual(hamlet.timezone, "")
+
+        self.assertEqual(iago.night_mode, True)
+        self.assertEqual(cordelia.night_mode, True)
+        self.assertEqual(hamlet.night_mode, False)
+
+        self.assertEqual(iago.enable_offline_email_notifications, False)
+        self.assertEqual(cordelia.enable_offline_email_notifications, False)
+        self.assertEqual(hamlet.enable_offline_email_notifications, True)
+
+        self.assertEqual(iago.enable_stream_push_notifications, True)
+        self.assertEqual(cordelia.enable_stream_push_notifications, True)
+        self.assertEqual(hamlet.enable_stream_push_notifications, False)
+
 class ActivateTest(ZulipTestCase):
     def test_basics(self) -> None:
         user = self.example_user('hamlet')