diff --git a/doc/requirements.txt b/doc/requirements.txt
index 71e8cb920eeef984e577fe4ff3933369c0e245ef..d01b7f9699529d02f8b91fb82e2f6e4f3998166c 100644
--- a/doc/requirements.txt
+++ b/doc/requirements.txt
@@ -7,7 +7,8 @@
 # be installed in a specific order.
 openstackdocstheme>=1.18.1 # Apache-2.0
 reno>=2.5.0 # Apache-2.0
-sphinx!=1.6.6,!=1.6.7,>=1.6.2 # BSD
+sphinx!=1.6.6,!=1.6.7,>=1.6.2,<2.0.0;python_version=='2.7' # BSD
+sphinx!=1.6.6,!=1.6.7,>=1.6.2;python_version>='3.4' # BSD
 
 # The below is rewquired to build testing module reference
 mock>=2.0.0 # BSD