diff --git a/requirements_dev.txt b/requirements_dev.txt
index 47c972e..463c27d 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -5,7 +5,7 @@ watchdog==0.8.3
 flake8==2.6.0
 tox==2.3.1
 coverage==4.1
-Sphinx==1.4.8
+Sphinx==3.3.1
 cryptography==1.7
 PyYAML==3.11
 pytest==2.9.2