diff --git a/test-requirements.txt b/test-requirements.txt
index c446262..f512e59 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -16,7 +16,7 @@ mox3>=0.20.0 # Apache-2.0
 testtools>=2.2.0 # MIT
 
 # For docs
-sphinx>=1.6.2 # BSD
+sphinx!=1.6.6,>=1.6.2 # BSD
 openstackdocstheme>=1.17.0 # Apache-2.0
 reno>=2.5.0 # Apache-2.0