diff --git a/doc/requirements.txt b/doc/requirements.txt
index 966197a1d..d204a868f 100644
--- a/doc/requirements.txt
+++ b/doc/requirements.txt
@@ -2,7 +2,8 @@
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
 openstackdocstheme>=1.20.0 # Apache-2.0
-sphinx>=1.6.5,!=1.6.6,!=1.6.7 # BSD
+sphinx>=1.6.5,!=1.6.6,!=1.6.7,<2.0.0;python_version=='2.7' # BSD
+sphinx>=1.6.5,!=1.6.6,!=1.6.7;python_version>='3.4' # BSD
 sphinxcontrib-pecanwsme>=0.8.0 # Apache-2.0
 reno>=2.7.0 # Apache-2.0
 sphinxcontrib-apidoc>=0.2.0  # BSD