diff --git a/test-requirements.txt b/test-requirements.txt
index 732c1f7fe..ed29fcf59 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -17,7 +17,7 @@ mox3>=0.20.0 # Apache-2.0
 
 # Docs Requirements
 openstackdocstheme>=1.17.0 # Apache-2.0
-sphinx>=1.6.2 # BSD
+sphinx!=1.6.6,>=1.6.2 # BSD
 reno>=2.5.0 # Apache-2.0
 
 # Horizon requirements