diff -u b/core/themes/classy/templates/misc/status-messages.html.twig b/core/themes/classy/templates/misc/status-messages.html.twig
--- b/core/themes/classy/templates/misc/status-messages.html.twig
+++ b/core/themes/classy/templates/misc/status-messages.html.twig
@@ -23,8 +23,10 @@
  * @see template_preprocess_status_messages()
  */
 #}
+{% if message_list is not empty %}
+  {{ attach_library('classy/messages') }}
+{% endif %}
 {% block messages %}
-{{ attach_library('classy/messages') }}
 {% for type, messages in message_list %}
   {%
     set classes = [