diff --git a/requirements_dev.txt b/requirements_dev.txt
index 7471224..0c8b9a7 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -5,7 +5,7 @@ watchdog==0.10.3
 flake8==3.8.4
 tox==3.20.1
 coverage==5.3
-Sphinx==3.2.1
+Sphinx==3.3.1
 cryptography==3.3.1
 PyYAML==5.3.1
 pytest==5.3.5