diff --git a/test-requirements.txt b/test-requirements.txt
index 2db0d6967..c1a641031 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -1,7 +1,7 @@
 # Nodepool uses hacking for its dependencies
 hacking>=0.10.2,<0.11
 coverage
-sphinx>=1.5.1
+sphinx>=1.5.1,<1.6
 sphinxcontrib-programoutput
 fixtures>=0.3.12
 mock>=1.0