diff --git a/test-requirements.txt b/test-requirements.txt
index be8a39d..e179eb3 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -7,7 +7,7 @@ hacking>=1.1.0,<1.2.0 # Apache-2.0
 coverage!=4.4,>=4.0 # Apache-2.0
 python-subunit>=1.0.0 # Apache-2.0/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
 stestr>=2.0.0 # Apache-2.0
 oslotest>=3.2.0 # Apache-2.0
 testscenarios>=0.4 # Apache-2.0/BSD