diff --git a/requirements_dev.txt b/requirements_dev.txt
index 9f400f4..3e7f15d 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -4,6 +4,6 @@ wheel==0.30.0
 flake8==3.5.0
 tox==3.2.1
 coverage==4.5.1
-Sphinx==1.8.0
+Sphinx==5.1.0
 pytest==3.8.0
 pytest-runner==4.0