diff --git a/doc/conf.py b/doc/conf.py
index 7322c30c72c8fe367a164ce72e1bc30c6e57f2f9..5ae704b58b299f453218e362de3c3cc9a0688731 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -31,8 +31,6 @@ extensions = [
   'sphinx.ext.autosummary',
   'sphinx.ext.doctest',
   'sphinx.ext.intersphinx',
-  'breathe',
-  'sphinxcontrib.restbuilder',
   ]
 
 # The viewcode extension appeared only on Sphinx >= 1.0.0