diff --git a/python/tox.ini b/python/tox.ini
index 98158a9d..c664fc77 100644
--- a/python/tox.ini
+++ b/python/tox.ini
@@ -38,8 +38,9 @@ commands =
     rst-lint --encoding 'utf-8' README.rst
 
 [testenv:doc]
+basepython = python3.5
 deps =
-    sphinx==1.8.5
+    sphinx==2.0.1
     breathe
 
 changedir = doc