diff --git a/flake.nix b/flake.nix
index da8ae84..b242176 100644
--- a/flake.nix
+++ b/flake.nix
@@ -124,7 +124,7 @@
           (pkgs.python3.withPackages (
             p: with p; [
               sphinx
-              sphinx_rtd_theme
+              sphinx-rtd-theme
               myst-parser
               linkify-it-py
             ]