diff --git a/scikeras/wrappers.py b/scikeras/wrappers.py
index 5ca51691..dbade3d6 100644
--- a/scikeras/wrappers.py
+++ b/scikeras/wrappers.py
@@ -503,7 +503,7 @@ def _fit_keras_model(
         # collect parameters
         params = self.get_params()
         fit_args = route_params(params, destination="fit", pass_filter=self._fit_kwargs)
-        fit_args["sample_weight"] = sample_weight
+        fit_args["sample_weight"] = [sample_weight]
         fit_args["epochs"] = initial_epoch + epochs
         fit_args["initial_epoch"] = initial_epoch
         fit_args.update(kwargs)