diff --git a/web/modals/threads/members/members-list.react.js b/web/modals/threads/members/members-list.react.js
--- a/web/modals/threads/members/members-list.react.js
+++ b/web/modals/threads/members/members-list.react.js
@@ -25,7 +25,8 @@
   const hasMembers = threadMembers.length > 0;
 
   const groupedByFirstLetterMembers = React.useMemo(
-    () => _groupBy(member => stringForUser(member)[0])(threadMembers),
+    () =>
+      _groupBy(member => stringForUser(member)[0].toLowerCase())(threadMembers),
     [threadMembers],
   );