diff --git a/test-requirements.txt b/test-requirements.txt
index 1b4d09f..5f6938b 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -5,7 +5,7 @@
 hacking<0.13,>=0.12.0 # Apache-2.0
 
 sphinx!=1.6.6,!=1.6.7,>=1.6.2,<2.0.0;python_version=='2.7'  # BSD
-sphinx!=1.6.6,!=1.6.7,>=1.6.2;python_version>='3.4'  # BSD
+sphinx!=1.6.6,!=1.6.7,!=2.1.0,>=1.6.2;python_version>='3.4'  # BSD
 openstackdocstheme>=1.18.1 # Apache-2.0
 # releasenotes
 reno>=2.5.0 # Apache-2.0