diff --git a/dev-requirements.txt b/dev-requirements.txt
index fd1a6a90..fbdb5664 100644
--- a/dev-requirements.txt
+++ b/dev-requirements.txt
@@ -106,7 +106,7 @@ six==1.12.0
 smmap2==2.0.5             # via gitdb2
 snowballstemmer==2.0.0    # via sphinx
 sphinx-autodoc-annotation==1.0.post1
-sphinx==2.3.1
+sphinx==3.5.2
 sphinxcontrib-applehelp==1.0.1  # via sphinx
 sphinxcontrib-devhelp==1.0.1  # via sphinx
 sphinxcontrib-htmlhelp==1.0.2  # via sphinx