diff --git a/django/contrib/admin/templates/admin/base.html b/django/contrib/admin/templates/admin/base.html
index 7838bba6a5..67fe27529c 100644
--- a/django/contrib/admin/templates/admin/base.html
+++ b/django/contrib/admin/templates/admin/base.html
@@ -30,7 +30,7 @@
     {% endif %}
 
         {% if messages %}
-        <ul class="messagelist">{% for message in messages %}<li>{{ message }}</li>{% endfor %}</ul>
+        <ul class="messagelist">{% for message in messages %}<li>{{ message|escape }}</li>{% endfor %}</ul>
         {% endif %}
 
     <!-- Content -->