diff --git a/doc/conf.py b/doc/conf.py
index f7dc802..0a03634 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -126,7 +126,7 @@ pygments_style = "sphinx"
 # The theme to use for HTML and HTML Help pages.  See the documentation for
 # a list of builtin themes.
 if on_rtd:
-    html_theme = "default"
+    html_theme = "sphinx_rtd_theme"
     print("recognized execution on RTD")
 else:
     try: