diff --git a/assets/javascripts/discourse/components/topic-level-assign-menu.js b/assets/javascripts/discourse/components/topic-level-assign-menu.js
index 942dd3ab..adc1d56b 100644
--- a/assets/javascripts/discourse/components/topic-level-assign-menu.js
+++ b/assets/javascripts/discourse/components/topic-level-assign-menu.js
@@ -65,7 +65,7 @@ export default {
     const topic = this.topic;
 
     if (topic.assigned_to_user || topic.hasAssignedPosts()) {
-      return unassignUsersButton(topic.assignees());
+      return unassignUsersButton(topic.uniqueAssignees());
     } else if (topic.assigned_to_group) {
       return unassignGroupButton(topic.assigned_to_group);
     }
diff --git a/assets/javascripts/discourse/initializers/extend-for-assigns.js b/assets/javascripts/discourse/initializers/extend-for-assigns.js
index 3e430b9a..dcde7df4 100644
--- a/assets/javascripts/discourse/initializers/extend-for-assigns.js
+++ b/assets/javascripts/discourse/initializers/extend-for-assigns.js
@@ -54,6 +54,12 @@ function extendTopicModel(api) {
       return result;
     },
 
+    uniqueAssignees() {
+      const map = new Map();
+      this.assignees().forEach((user) => map.set(user.username, user));
+      return [...map.values()];
+    },
+
     assignedPosts() {
       if (!this.indirectly_assigned_to) {
         return [];