diff --git a/backends/apple/mps/operators/shape_ops.py b/backends/apple/mps/operators/shape_ops.py
index 76c559018be..d75e42d1c45 100644
--- a/backends/apple/mps/operators/shape_ops.py
+++ b/backends/apple/mps/operators/shape_ops.py
@@ -243,10 +243,12 @@ def define_node(
         split_sizes = eval_shape(cast(torch.SymInt, node.args[1]))
         dim = cast(int, node.args[2])
         input_shape = get_shape(get_input_node(node, 0))
+        if dim < 0:
+            dim += len(input_shape)
 
         if dim < 0 or dim >= len(input_shape):
             raise RuntimeError(
-                f"split_copy: dim {dim} out of range for input tensor with {len(input_shape)} dimensions"
+                f"split_copy: dim {cast(int, node.args[2])} out of range for input tensor with {len(input_shape)} dimensions"
             )
 
         mps_node = MPSNode(