diff --git a/requirements_dev.txt b/requirements_dev.txt
index 3e622af..a066e91 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -6,7 +6,7 @@ pytest==3.6.1
 pytest-cov==2.5.1
 pytest-mock==1.10.0
 tox==3.0.0
-Sphinx==1.7.5
+Sphinx==3.5.1
 capturer==2.4
 requests-mock==1.5.0
 -r requirements.txt