diff --git a/keras_core/layers/merging/base_merge.py b/keras_core/layers/merging/base_merge.py
index 7c44c39e2..2837c2924 100644
--- a/keras_core/layers/merging/base_merge.py
+++ b/keras_core/layers/merging/base_merge.py
@@ -61,7 +61,7 @@ def _compute_elemwise_op_output_shape(self, shape1, shape2):
 
     def build(self, input_shape):
         # Used purely for shape validation.
-        if not isinstance(input_shape[0], tuple):
+        if not isinstance(input_shape[0], (tuple, list)):
             raise ValueError(
                 "A merge layer should be called on a list of inputs. "
                 f"Received: input_shape={input_shape} (not a list of shapes)"
diff --git a/keras_core/layers/merging/concatenate.py b/keras_core/layers/merging/concatenate.py
index 79e3ca0d8..5d32ebdbe 100644
--- a/keras_core/layers/merging/concatenate.py
+++ b/keras_core/layers/merging/concatenate.py
@@ -39,7 +39,9 @@ def __init__(self, axis=-1, **kwargs):
 
     def build(self, input_shape):
         # Used purely for shape validation.
-        if len(input_shape) < 1 or not isinstance(input_shape[0], tuple):
+        if len(input_shape) < 1 or not isinstance(
+            input_shape[0], (tuple, list)
+        ):
             raise ValueError(
                 "A `Concatenate` layer should be called on a list of "
                 f"at least 1 input. Received: input_shape={input_shape}"