diff --git a/app/assets/stylesheets/common/base/topic-post.scss b/app/assets/stylesheets/common/base/topic-post.scss
index 3c0a163394..1a9a4cf73b 100644
--- a/app/assets/stylesheets/common/base/topic-post.scss
+++ b/app/assets/stylesheets/common/base/topic-post.scss
@@ -871,6 +871,9 @@ a.mention-group {
   color: $primary;
   padding: 1em;
   margin-bottom: 1em;
+  max-width: calc(
+    #{$topic-body-width} + #{$topic-avatar-width} - #{$topic-body-width-padding} + 3px
+  );
 
   p {
     margin: 0;