diff --git a/CHANGELOG.txt b/CHANGELOG.txt
index 974f4cdeb3..e4febee949 100644
--- a/CHANGELOG.txt
+++ b/CHANGELOG.txt
@@ -14,6 +14,7 @@ Changelog
  * Refactored the way forms are constructed for the page editor, to allow custom forms to be used
  * Notification message on publish now indicates whether the page is being published now or scheduled for publication in future (Chris Rogers)
  * Server errors when uploading images / documents through the chooser modal are now reported back to the user (Nigel Fletton)
+ * Added a hook `insert_global_admin_css` for inserting custom CSS throughout the admin backend (Tom Dyson)
  * New translations for Hungarian, Swedish (Sweden) and Turkish
  * Fix: Custom page managers no longer raise an error when used on an abstract model
  * Fix: Wagtail's migrations are now all reversible (benjaoming)
diff --git a/docs/reference/hooks.rst b/docs/reference/hooks.rst
index 12a4c90a84..ac5023b6ab 100644
--- a/docs/reference/hooks.rst
+++ b/docs/reference/hooks.rst
@@ -244,6 +244,27 @@ Hooks for customising the editing interface for pages and snippets.
       + 'demo/css/vendor/font-awesome/css/font-awesome.min.css">')
 
 
+.. _insert_global_admin_css:
+
+``insert_global_admin_css``
+~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Add additional CSS files or snippets to all admin pages.
+
+.. code-block:: python
+
+  from django.utils.html import format_html
+  from django.conf import settings
+
+  from wagtail.wagtailcore import hooks
+
+  @hooks.register('insert_global_admin_css')
+  def global_admin_css():
+    return format_html('<link rel="stylesheet" href="' \
+    + settings.STATIC_URL \
+    + 'my/wagtail/theme.css">')
+
+
 .. _insert_editor_js:
 
 ``insert_editor_js``
diff --git a/docs/releases/1.4.rst b/docs/releases/1.4.rst
index 1df2411b89..203db6fb9c 100644
--- a/docs/releases/1.4.rst
+++ b/docs/releases/1.4.rst
@@ -48,6 +48,7 @@ Minor features
  * Refactored the way forms are constructed for the page editor, to allow custom forms to be used
  * Notification message on publish now indicates whether the page is being published now or scheduled for publication in future (Chris Rogers)
  * Server errors when uploading images / documents through the chooser modal are now reported back to the user (Nigel Fletton)
+ * Added a hook ``insert_global_admin_css`` for inserting custom CSS throughout the admin backend (Tom Dyson)
  * New translations for Hungarian, Swedish (Sweden) and Turkish
 
 
diff --git a/wagtail/wagtailadmin/templates/wagtailadmin/admin_base.html b/wagtail/wagtailadmin/templates/wagtailadmin/admin_base.html
index cc370eb37d..74dcc5ca1c 100644
--- a/wagtail/wagtailadmin/templates/wagtailadmin/admin_base.html
+++ b/wagtail/wagtailadmin/templates/wagtailadmin/admin_base.html
@@ -5,6 +5,7 @@
     <link rel="stylesheet" href="{% static 'wagtailadmin/css/vendor/jquery-ui/jquery-ui-1.10.3.verdant.css' %}" />
     <link rel="stylesheet" href="{% static 'wagtailadmin/css/vendor/jquery.tagit.css' %}">
     <link rel="stylesheet" href="{% static 'wagtailadmin/css/core.css' %}" type="text/css" />
+    {% hook_output 'insert_global_admin_css' %}
 
     {% block extra_css %}{% endblock %}
 {% endblock %}