diff --git a/django/contrib/admin/templates/admin/login.html b/django/contrib/admin/templates/admin/login.html
index a955c871f7..4c0dc63dcf 100644
--- a/django/contrib/admin/templates/admin/login.html
+++ b/django/contrib/admin/templates/admin/login.html
@@ -34,7 +34,7 @@
 
 {% if user.is_authenticated %}
 <p class="errornote">
-{% blocktrans with username=request.user.username trimmed %}
+{% blocktrans with username=request.user.get_username trimmed %}
     You are authenticated as {{ username }}, but are not authorized to
     access this page. Would you like to login to a different account?
 {% endblocktrans %}
diff --git a/docs/releases/1.9.3.txt b/docs/releases/1.9.3.txt
index cd7d674864..ef95681024 100644
--- a/docs/releases/1.9.3.txt
+++ b/docs/releases/1.9.3.txt
@@ -42,3 +42,7 @@ Bugfixes
   regressed in Django 1.9 (:ticket:`26253`).
 
 * Fixed ``BoundField`` to reallow slices of subwidgets (:ticket:`26267`).
+
+* Changed the admin's "permission denied" message in the login template to use
+  ``get_username`` instead of ``username`` to support custom user models
+  (:ticket:`26231`).