diff --git a/test-requirements.txt b/test-requirements.txt
index 19e02360d7..ea93dc6f83 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -2,7 +2,7 @@
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
 hacking!=0.13.0,<0.14,>=0.12.0 # Apache-2.0
-sphinx>=1.5.1 # BSD
+sphinx>=1.5.1,<1.6.0 # BSD
 oslosphinx>=4.7.0 # Apache-2.0
 bashate>=0.2 # Apache-2.0
 PyYAML>=3.10.0 # MIT