diff --git a/test-requirements.txt b/test-requirements.txt
index a5678eb0..bf8452b4 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -13,7 +13,7 @@ testscenarios>=0.4 # Apache-2.0/BSD
 stestr>=2.0.0 # Apache-2.0
 mock>=1.2 # 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
+sphinx!=1.6.6,!=1.6.7,!=2.1.0,>=1.6.2;python_version>='3.4' # BSD
 openstackdocstheme>=1.20.0 # Apache-2.0
 oslotest>=1.10.0 # Apache-2.0
 sphinxcontrib-httpdomain>=1.6.0 # BSD