diff --git a/setup.py b/setup.py
index 59e76935f0..a24b3a7510 100755
--- a/setup.py
+++ b/setup.py
@@ -71,7 +71,7 @@
 extras_require = {
     'docs': [
         'sphinx>=3',
-        'sphinx_rtd_theme'],
+        'sphinx-rtd-theme==1.3.0rc1'],
     'tests': [
         'flake8',
         'pytest',