diff --git a/test-requirements.txt b/test-requirements.txt
index f3e74e0..9f37a05 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -5,4 +5,4 @@
 # Hacking already pins down pep8, pyflakes and flake8
 hacking!=0.13.0,<0.14,>=0.12.0 # Apache-2.0
 openstackdocstheme>=1.17.0 # Apache-2.0
-sphinx>=1.6.2 # BSD
+sphinx!=1.6.6,>=1.6.2 # BSD