diff --git a/lib/pep621.nix b/lib/pep621.nix
index 5d92368..aa76bc6 100644
--- a/lib/pep621.nix
+++ b/lib/pep621.nix
@@ -1,4 +1,4 @@
-{ lib, pep440, pep508, pep518, ... }:
+{ lib, pep440, pep508, pep518, pypa, ... }:
 let
   inherit (builtins) mapAttrs foldl' split filter elem;
   inherit (lib) isString filterAttrs fix;
@@ -65,7 +65,8 @@ fix (self: {
   */
   getDependenciesNames =
     let
-      getNames = map (dep: dep.name);
+      normalize = pypa.normalizePackageName;
+      getNames = map (dep: normalize dep.name);
     in
     dependencies: {
       dependencies = getNames dependencies.dependencies;