diff --git a/test-requirements.txt b/test-requirements.txt
index 5e215068a..a0842c55f 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -8,7 +8,7 @@ coverage>=4.0 # Apache-2.0
 fixtures>=3.0.0 # Apache-2.0/BSD
 mock>=2.0 # BSD
 python-subunit>=0.0.18 # Apache-2.0/BSD
-sphinx>=1.5.1 # BSD
+sphinx>=1.5.1,<2.0.0 # BSD
 sphinxcontrib-httpdomain # BSD
 stestr>=2.0.0 # Apache-2.0
 testtools>=1.4.0 # MIT