diff --git a/doc/api/api_changes/2017-12-02-AL.rst b/doc/api/api_changes/2017-12-02-AL.rst
new file mode 100644
index 000000000000..2fabbc598824
--- /dev/null
+++ b/doc/api/api_changes/2017-12-02-AL.rst
@@ -0,0 +1,6 @@
+Deprecations
+````````````
+
+The unused ``FigureManagerBase.show_popup`` method is deprecated.  This 
+introduced in e945059b327d42a99938b939a1be867fa023e7ba in 2005 but never built
+out into any of the backends.
diff --git a/doc/devel/MEP/MEP27.rst b/doc/devel/MEP/MEP27.rst
index 57b0540a4c91..63592cf475a3 100644
--- a/doc/devel/MEP/MEP27.rst
+++ b/doc/devel/MEP/MEP27.rst
@@ -114,9 +114,6 @@ The description of this MEP gives us most of the solution:
 +--------------------------------------+------------------------------+---------------------+--------------------------------+
 |key_press                             |key_press                     |                     |                                |
 +--------------------------------------+------------------------------+---------------------+--------------------------------+
-|show_popup                            |show_poup                     |                     |Not used anywhere in mpl, and   |
-|                                      |                              |                     |does nothing.                   |
-+--------------------------------------+------------------------------+---------------------+--------------------------------+
 |get_window_title                      |                              |get_window_title     |                                |
 +--------------------------------------+------------------------------+---------------------+--------------------------------+
 |set_window_title                      |                              |set_window_title     |                                |
diff --git a/lib/matplotlib/backend_bases.py b/lib/matplotlib/backend_bases.py
index 25afd45238bd..37757620c2e5 100644
--- a/lib/matplotlib/backend_bases.py
+++ b/lib/matplotlib/backend_bases.py
@@ -2696,6 +2696,7 @@ def key_press(self, event):
         if rcParams['toolbar'] != 'toolmanager':
             key_press_handler(event, self.canvas, self.canvas.toolbar)
 
+    @cbook.deprecated("2.2")
     def show_popup(self, msg):
         """Display message in a popup -- GUI only."""