diff --git a/app/models/user_summary.rb b/app/models/user_summary.rb
index 69796d9fc1a..9edda802f38 100644
--- a/app/models/user_summary.rb
+++ b/app/models/user_summary.rb
@@ -196,9 +196,13 @@ protected
     user_ids.map do |user_id|
       lookup_hash = lookup[user_id]
 
-      UserWithCount.new(
-        lookup_hash.attributes.merge(count: user_hash[user_id])
-      ) if lookup_hash.present?
+      if lookup_hash.present?
+        primary_group = lookup.primary_groups[user_id]
+
+        UserWithCount.new(
+          lookup_hash.attributes.merge(count: user_hash[user_id], primary_group: primary_group)
+        )
+      end
     end.compact.sort_by { |u| -u[:count] }
   end
 
diff --git a/app/serializers/user_summary_serializer.rb b/app/serializers/user_summary_serializer.rb
index 65d0250de13..6776fb50ebe 100644
--- a/app/serializers/user_summary_serializer.rb
+++ b/app/serializers/user_summary_serializer.rb
@@ -21,7 +21,18 @@ class UserSummarySerializer < ApplicationSerializer
   end
 
   class UserWithCountSerializer < ApplicationSerializer
-    attributes :id, :username, :name, :count, :avatar_template
+    attributes :id,
+               :username,
+               :name,
+               :count,
+               :avatar_template,
+               :admin,
+               :moderator,
+               :trust_level,
+               :primary_group_flair_url,
+               :primary_group_flair_bg_color,
+               :primary_group_flair_color,
+               :primary_group_name
 
     def include_name?
       SiteSetting.enable_names?
@@ -30,6 +41,22 @@ class UserSummarySerializer < ApplicationSerializer
     def avatar_template
       User.avatar_template(object[:username], object[:uploaded_avatar_id])
     end
+
+    def primary_group_flair_url
+      object.primary_group&.flair_icon
+    end
+
+    def primary_group_flair_bg_color
+      object.primary_group&.flair_bg_color
+    end
+
+    def primary_group_flair_color
+      object.primary_group&.flair_color
+    end
+
+    def primary_group_name
+      object.primary_group&.name
+    end
   end
 
   class CategoryWithCountsSerializer < ApplicationSerializer