diff --git a/doc/conf.py b/doc/conf.py
index 90a71ef59085f8fd4aee7c3591225865c44c534d..67f8c8870ba0d4a14183879abcfbc45b9ee6aa5f 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -31,7 +31,6 @@ extensions = [
   'sphinx.ext.autosummary',
   'sphinx.ext.doctest',
   'sphinx.ext.intersphinx',
-  'matplotlib.sphinxext.plot_directive',
   ]
 
 # The viewcode extension appeared only on Sphinx >= 1.0.0