diff --git a/app/views/projects/buttons/_notifications.html.haml b/app/views/projects/buttons/_notifications.html.haml
index 745983ace7e..a8b728527c8 100644
--- a/app/views/projects/buttons/_notifications.html.haml
+++ b/app/views/projects/buttons/_notifications.html.haml
@@ -12,8 +12,8 @@
             %button.dropdown-new.btn.btn-default.has-tooltip.notifications-btn#notifications-button{ type: "button", title: _("Notification setting - %{notification_title}") % { notification_title: notification_title(notification_setting.level) }, class: "#{btn_class}", "aria-label" => _("Notification setting - %{notification_title}") % { notification_title: notification_title(notification_setting.level) }, data: { container: "body", toggle: "modal", target: "#" + notifications_menu_identifier("modal", notification_setting), display: 'static' } }
               = sprite_icon("notifications", css_class: "icon notifications-icon js-notifications-icon")
               %span.js-notification-loading.fa.hidden
-            %button.btn.dropdown-toggle{ data: { toggle: "dropdown", target: notifications_menu_identifier("dropdown", notification_setting), flip: "false" } }
-              = sprite_icon("arrow-down", css_class: "icon")
+            %button.btn.dropdown-toggle{ data: { toggle: "dropdown", target: notifications_menu_identifier("dropdown", notification_setting), flip: "false" }, class: "#{btn_class}" }
+              = sprite_icon("arrow-down", css_class: "icon mr-0")
               .sr-only Toggle dropdown
           - else
             %button.dropdown-new.btn.btn-default.has-tooltip.notifications-btn#notifications-button{ type: "button", title: "Notification setting - #{notification_title(notification_setting.level)}", class: "#{btn_class}", "aria-label" => "Notification setting: #{notification_title(notification_setting.level)}", data: { container: "body", toggle: "dropdown", target: notifications_menu_identifier("dropdown", notification_setting), flip: "false" } }
diff --git a/changelogs/unreleased/fix-55956-oversized-dropdown-button-custom-notifications.yml b/changelogs/unreleased/fix-55956-oversized-dropdown-button-custom-notifications.yml
new file mode 100644
index 00000000000..e33699a2112
--- /dev/null
+++ b/changelogs/unreleased/fix-55956-oversized-dropdown-button-custom-notifications.yml
@@ -0,0 +1,5 @@
+---
+title: Fixed oversized custom project notification selector dropdown
+merge_request: 24557
+author:
+type: fixed