diff --git a/extensions/flags/composer.json b/extensions/flags/composer.json
index 5773d56d4..f7a74c24f 100644
--- a/extensions/flags/composer.json
+++ b/extensions/flags/composer.json
@@ -29,7 +29,7 @@
         "flarum-extension": {
             "title": "Flags",
             "icon": {
-                "name": "fa fa-flag",
+                "name": "fas fa-flag",
                 "backgroundColor": "#D659B5",
                 "color": "#fff"
             }
diff --git a/extensions/flags/js/admin/src/main.js b/extensions/flags/js/admin/src/main.js
index 38fc95018..666577a17 100644
--- a/extensions/flags/js/admin/src/main.js
+++ b/extensions/flags/js/admin/src/main.js
@@ -9,7 +9,7 @@ app.initializers.add('flarum-flags', () => {
 
   extend(PermissionGrid.prototype, 'moderateItems', items => {
     items.add('viewFlags', {
-      icon: 'fa fa-flag',
+      icon: 'fas fa-flag',
       label: app.translator.trans('flarum-flags.admin.permissions.view_flags_label'),
       permission: 'discussion.viewFlags'
     }, 65);
@@ -17,7 +17,7 @@ app.initializers.add('flarum-flags', () => {
 
   extend(PermissionGrid.prototype, 'replyItems', items => {
     items.add('flagPosts', {
-      icon: 'fa fa-flag',
+      icon: 'fas fa-flag',
       label: app.translator.trans('flarum-flags.admin.permissions.flag_posts_label'),
       permission: 'discussion.flagPosts'
     }, 70);
diff --git a/extensions/flags/js/forum/src/addFlagControl.js b/extensions/flags/js/forum/src/addFlagControl.js
index 3121f5c0c..9e3d82049 100644
--- a/extensions/flags/js/forum/src/addFlagControl.js
+++ b/extensions/flags/js/forum/src/addFlagControl.js
@@ -10,7 +10,7 @@ export default function() {
     if (post.isHidden() || post.contentType() !== 'comment' || !post.canFlag() || post.user() === app.session.user) return;
 
     items.add('flag',
-      <Button icon="fa fa-flag" onclick={() => app.modal.show(new FlagPostModal({post}))}>{app.translator.trans('flarum-flags.forum.post_controls.flag_button')}</Button>
+      <Button icon="fas fa-flag" onclick={() => app.modal.show(new FlagPostModal({post}))}>{app.translator.trans('flarum-flags.forum.post_controls.flag_button')}</Button>
     );
   });
 }
diff --git a/extensions/flags/js/forum/src/components/FlagList.js b/extensions/flags/js/forum/src/components/FlagList.js
index 9c9214175..6781cf36f 100644
--- a/extensions/flags/js/forum/src/components/FlagList.js
+++ b/extensions/flags/js/forum/src/components/FlagList.js
@@ -37,7 +37,7 @@ export default class FlagList extends Component {
                       if (!isInitialized) $(element).on('click', () => app.cache.flagIndex = post);
                     }}>
                       {avatar(post.user())}
-                      {icon('fa fa-flag', {className: 'Notification-icon'})}
+                      {icon('fas fa-flag', {className: 'Notification-icon'})}
                       <span className="Notification-content">
                         {app.translator.trans('flarum-flags.forum.flagged_posts.item_text', {username: username(post.user()), em: <em/>, discussion: post.discussion().title()})}
                       </span>
diff --git a/extensions/flags/js/forum/src/components/FlagsDropdown.js b/extensions/flags/js/forum/src/components/FlagsDropdown.js
index 039a7572a..60a7e5327 100644
--- a/extensions/flags/js/forum/src/components/FlagsDropdown.js
+++ b/extensions/flags/js/forum/src/components/FlagsDropdown.js
@@ -5,7 +5,7 @@ import FlagList from 'flarum/flags/components/FlagList';
 export default class FlagsDropdown extends NotificationsDropdown {
   static initProps(props) {
     props.label = props.label || app.translator.trans('flarum-flags.forum.flagged_posts.tooltip');
-    props.icon = props.icon || 'fa fa-flag';
+    props.icon = props.icon || 'fas fa-flag';
 
     super.initProps(props);
   }