diff --git a/zerver/lib/actions.py b/zerver/lib/actions.py
index bf09bbf731..d3b718e560 100644
--- a/zerver/lib/actions.py
+++ b/zerver/lib/actions.py
@@ -257,13 +257,22 @@ def add_new_user_history(user_profile, streams):
     recipients = Recipient.objects.filter(type=Recipient.STREAM,
                                           type_id__in=[stream.id for stream in streams
                                                        if not stream.invite_only])
-    messages = Message.objects.filter(recipient_id__in=recipients, pub_date__gt=one_week_ago).order_by("-id")[0:100]
-    if len(messages) > 0:
-        ums_to_create = [UserMessage(user_profile=user_profile, message=message,
-                                     flags=UserMessage.flags.read)
-                         for message in messages]
+    recent_messages = Message.objects.filter(recipient_id__in=recipients,
+                                             pub_date__gt=one_week_ago).order_by("-id")
+    message_ids_to_use = list(recent_messages.values_list('id', flat=True)[0:100])
+    if len(message_ids_to_use) == 0:
+        return
 
-        UserMessage.objects.bulk_create(ums_to_create)
+    # Handle the race condition where a message arrives between
+    # bulk_add_subscriptions above and the Message query just above
+    already_ids = set(UserMessage.objects.filter(message_id__in=message_ids_to_use,
+                                                 user_profile=user_profile).values_list("message_id", flat=True))
+    ums_to_create = [UserMessage(user_profile=user_profile, message_id=message_id,
+                                 flags=UserMessage.flags.read)
+                     for message_id in message_ids_to_use
+                     if message_id not in already_ids]
+
+    UserMessage.objects.bulk_create(ums_to_create)
 
 # Does the processing for a new user account:
 # * Subscribes to default/invitation streams
diff --git a/zerver/tests/test_signup.py b/zerver/tests/test_signup.py
index 6862967f4a..7949421921 100644
--- a/zerver/tests/test_signup.py
+++ b/zerver/tests/test_signup.py
@@ -14,6 +14,7 @@ from zerver.views.invite import get_invitee_emails_set
 from zerver.models import (
     get_realm, get_realm_by_string_id, get_prereg_user_by_email, get_user_profile_by_email,
     PreregistrationUser, Realm, RealmAlias, Recipient, ScheduledJob, UserProfile, UserMessage,
+    Stream, Subscription,
 )
 
 from zerver.lib.actions import (
@@ -22,7 +23,8 @@ from zerver.lib.actions import (
 )
 
 from zerver.lib.initial_password import initial_password
-from zerver.lib.actions import do_deactivate_realm, do_set_realm_default_language
+from zerver.lib.actions import do_deactivate_realm, do_set_realm_default_language, \
+    add_new_user_history
 from zerver.lib.digest import send_digest_email
 from zerver.lib.notifications import enqueue_welcome_emails, one_click_unsubscribe_link
 from zerver.lib.test_helpers import find_key_by_email, queries_captured, \
@@ -124,6 +126,22 @@ class PublicURLTest(ZulipTestCase):
             self.assertEqual('success', data['result'])
             self.assertEqual('ABCD', data['google_client_id'])
 
+class AddNewUserHistoryTest(ZulipTestCase):
+    def test_add_new_user_history_race(self):
+        # type: () -> None
+        """Sends a message during user creation"""
+        # Create a user who hasn't had historical messages added
+        set_default_streams(get_realm_by_string_id("zulip"), ["Denmark", "Verona"])
+        with patch("zerver.lib.actions.add_new_user_history"):
+            self.register("test", "test")
+        user_profile = get_user_profile_by_email("test@zulip.com")
+
+        subs = Subscription.objects.select_related("recipient").filter(
+            user_profile=user_profile, recipient__type=Recipient.STREAM)
+        streams = Stream.objects.filter(id__in=[sub.recipient.type_id for sub in subs])
+        self.send_message("hamlet@zulip.com", streams[0].name, Recipient.STREAM, "test")
+        add_new_user_history(user_profile, streams)
+
 class PasswordResetTest(ZulipTestCase):
     """
     Log in, reset password, log out, log in with new password.