diff --git a/test-requirements.txt b/test-requirements.txt
index 1e1abe8..895e032 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -5,7 +5,7 @@
 hacking<0.13,>=0.12.0 # Apache-2.0
 
 coverage!=4.4,>=4.0 # Apache-2.0
-sphinx>=1.6.2 # BSD
+sphinx!=1.6.6,>=1.6.2 # BSD
 openstackdocstheme>=1.17.0 # Apache-2.0
 
 # releasenotes