diff --git a/rtd-requirements.txt b/rtd-requirements.txt
index 22954f6df..48a72910f 100644
--- a/rtd-requirements.txt
+++ b/rtd-requirements.txt
@@ -3,4 +3,4 @@ numpy>=1.4.1
 pyparsing==1.5.7
 sympy>=0.7.6
 sphinxcontrib-issuetracker
-sphinx>=1.4.2
+sphinx>=1.5