diff --git a/test-requirements.txt b/test-requirements.txt
index 76eb66860..0456af40e 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -21,11 +21,11 @@ python-subunit>=1.0.0 # Apache-2.0/BSD
 testrepository>=0.0.18 # Apache-2.0/BSD
 testscenarios>=0.4 # Apache-2.0/BSD
 testtools>=2.2.0 # MIT
-tempest>=17.1.0  # Apache-2.0
+tempest>=17.1.0 # Apache-2.0
 
 # documentation
 doc8>=0.6.0 # Apache-2.0
-sphinx>=1.6.2 # BSD
+sphinx!=1.6.6,>=1.6.2 # BSD
 os-api-ref>=1.4.0 # Apache-2.0
 reno>=2.5.0 # Apache-2.0
 openstackdocstheme>=1.17.0 # Apache-2.0