diff --git a/test-requirements.txt b/test-requirements.txt
index 10119c2..31a5240 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -17,7 +17,7 @@ oslo.utils>=3.33.0 # Apache-2.0
 stestr>=1.0.0 # Apache-2.0
 pexpect>=4.0.1
 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
 sphinxcontrib-pecanwsme>=0.8
 testtools>=0.9.36,!=1.2.0
 typing>=3.6; python_version>'2.7'