diff --git a/pkgs/development/python-modules/datamodel-code-generator/default.nix b/pkgs/development/python-modules/datamodel-code-generator/default.nix
index d247304b8ee2..f4a8c4377666 100644
--- a/pkgs/development/python-modules/datamodel-code-generator/default.nix
+++ b/pkgs/development/python-modules/datamodel-code-generator/default.nix
@@ -35,7 +35,10 @@ buildPythonPackage rec {
     hash = "sha256-CYNEpQFIWR7i7I7YJ5q/34KNhtQ7cjya97Z0fyeO5g8=";
   };
 
-  pythonRelaxDeps = [ "inflect" ];
+  pythonRelaxDeps = [
+    "inflect"
+    "isort"
+  ];
 
   build-system = [
     poetry-core