diff --git a/setup.cfg b/setup.cfg
index e4134433..44435e3f 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -79,7 +79,7 @@ test =
                                  # or brew install exempi
 docs =
     sphinx
-    sphinx_rtd_theme
+    sphinx-rtd-theme
     sphinx-issues
 extended_test =
     PyMuPDF == 1.13.4