diff --git a/app/javascript/mastodon/features/notifications_v2/components/avatar_group.tsx b/app/javascript/mastodon/features/notifications_v2/components/avatar_group.tsx
index 741938f62b..e1e25810d3 100644
--- a/app/javascript/mastodon/features/notifications_v2/components/avatar_group.tsx
+++ b/app/javascript/mastodon/features/notifications_v2/components/avatar_group.tsx
@@ -1,6 +1,7 @@
 import { Link } from 'react-router-dom';
 
 import { Avatar } from 'mastodon/components/avatar';
+import { NOTIFICATIONS_GROUP_MAX_AVATARS } from 'mastodon/models/notification_group';
 import { useAppSelector } from 'mastodon/store';
 
 const AvatarWrapper: React.FC<{ accountId: string }> = ({ accountId }) => {
@@ -19,7 +20,7 @@ export const AvatarGroup: React.FC<{ accountIds: string[] }> = ({
   accountIds,
 }) => (
   <div className='notification-group__avatar-group'>
-    {accountIds.slice(0, 7).map((accountId) => (
+    {accountIds.slice(0, NOTIFICATIONS_GROUP_MAX_AVATARS).map((accountId) => (
       <AvatarWrapper key={accountId} accountId={accountId} />
     ))}
   </div>
diff --git a/app/javascript/mastodon/models/notification_group.ts b/app/javascript/mastodon/models/notification_group.ts
index c8e078c747..4dc7229c31 100644
--- a/app/javascript/mastodon/models/notification_group.ts
+++ b/app/javascript/mastodon/models/notification_group.ts
@@ -9,6 +9,10 @@ import type {
 } from 'mastodon/api_types/notifications';
 import type { ApiReportJSON } from 'mastodon/api_types/reports';
 
+// Maximum number of avatars displayed in a notification group
+// This corresponds to the max lenght of `group.sampleAccountsIds`
+export const NOTIFICATIONS_GROUP_MAX_AVATARS = 6;
+
 interface BaseNotificationGroup
   extends Omit<BaseNotificationGroupJSON, 'sample_accounts'> {
   sampleAccountsIds: string[];
diff --git a/app/javascript/mastodon/reducers/notifications_groups.ts b/app/javascript/mastodon/reducers/notifications_groups.ts
index e42d753958..de4bab5afe 100644
--- a/app/javascript/mastodon/reducers/notifications_groups.ts
+++ b/app/javascript/mastodon/reducers/notifications_groups.ts
@@ -6,6 +6,7 @@ import {
   processNewNotificationForGroups,
 } from 'mastodon/actions/notification_groups';
 import {
+  NOTIFICATIONS_GROUP_MAX_AVATARS,
   createNotificationGroupFromJSON,
   createNotificationGroupFromNotificationJSON,
 } from 'mastodon/models/notification_group';
@@ -84,8 +85,11 @@ export const notificationsGroupsReducer =
 
           if (existingGroup && existingGroup.type !== 'gap') {
             // Update the existing group
-            existingGroup.sampleAccountsIds.unshift(notification.account.id);
-            existingGroup.sampleAccountsIds.pop();
+            if (
+              existingGroup.sampleAccountsIds.unshift(notification.account.id) >
+              NOTIFICATIONS_GROUP_MAX_AVATARS
+            )
+              existingGroup.sampleAccountsIds.pop();
 
             existingGroup.most_recent_notification_id = notification.id;
             existingGroup.page_max_id = notification.id;