diff --git a/js/forum/src/components/PostUser.js b/js/forum/src/components/PostUser.js
index 071c333ed..551e61eea 100644
--- a/js/forum/src/components/PostUser.js
+++ b/js/forum/src/components/PostUser.js
@@ -45,6 +45,7 @@ export default class PostUser extends Component {
 
     return (
       <div className="PostUser">
+        {useronline(user)}
         <h3>
           <a href={app.route.user(user)} config={m.route}>
             {avatar(user, {className: 'PostUser-avatar'})}{' '}{username(user)}
diff --git a/js/lib/helpers/useronline.js b/js/lib/helpers/useronline.js
new file mode 100644
index 000000000..dc4804850
--- /dev/null
+++ b/js/lib/helpers/useronline.js
@@ -0,0 +1,13 @@
+import icon from 'flarum/helpers/icon';
+
+/**
+ * The `useronline` helper displays a green circle if the user is online
+ *
+ * @param {User} user
+ * @return {Object}
+ */
+export default function useronline(user) {
+    if (user.lastSeenTime() && user.isOnline()) {
+        return <span className="UserOnline">{icon('circle')}</span>;
+    }
+}
diff --git a/less/forum/Post.less b/less/forum/Post.less
index e79c8e00c..44b0ec6ad 100644
--- a/less/forum/Post.less
+++ b/less/forum/Post.less
@@ -49,6 +49,16 @@
     font-size: 14px;
   }
 
+  .UserOnline {
+    & .icon {
+      font-size: 12px;
+    }
+
+    & .fa-circle {
+      color: @online-user-circle-color;
+    }
+  }
+
   .UserCard {
     position: absolute;
     top: -10px;