diff --git a/src/peft/tuners/tuners_utils.py b/src/peft/tuners/tuners_utils.py
index 02e6f2feb7..5abaac5e7f 100644
--- a/src/peft/tuners/tuners_utils.py
+++ b/src/peft/tuners/tuners_utils.py
@@ -1722,7 +1722,10 @@ def check_target_module_exists(config, key: str) -> bool | re.Match[str] | None:
             # TODO: It's still unclear how empty layers_pattern (None, [], or "") should behave
             # For now, empty layers_pattern means any layer pattern is ok
             if layers_pattern is None or len(layers_pattern) == 0:
-                layer_index = re.match(r".*\.[^.]*\.(\d+)\.", key)
+                # Use non-greedy .*? to match the FIRST digit group, not the last
+                # This prevents MoE expert indices from being matched instead of layer indices
+                # e.g., for "model.layers.1.mlp.experts.0.up_proj", we want to match "1" not "0"
+                layer_index = re.match(r".*?\.[^.]*\.(\d+)\.", key)
             else:
                 layers_pattern = [layers_pattern] if isinstance(layers_pattern, str) else layers_pattern
                 for pattern in layers_pattern:
diff --git a/tests/test_tuners_utils.py b/tests/test_tuners_utils.py
index e93f87610b..d946d12627 100644
--- a/tests/test_tuners_utils.py
+++ b/tests/test_tuners_utils.py
@@ -128,6 +128,16 @@
     ("blocks.1.bias", ["weight"], [1], ["blocks"], False),
     ("mlp.blocks.1.weight", ["weight"], [1], ["blocks"], True),
     ("mlp.blocks.1.bias", ["weight"], [1], ["blocks"], False),
+    # MoE models: layers_to_transform should match layer index, not expert index
+    # For "model.layers.1.mlp.experts.0.up_proj", should match layer 1, not expert 0
+    ("model.layers.1.mlp.experts.0.up_proj", ["up_proj"], [1], ["layers"], True),
+    ("model.layers.1.mlp.experts.0.up_proj", ["up_proj"], [0], ["layers"], False),  # expert 0, but layer 1
+    ("model.layers.1.mlp.experts.1.up_proj", ["up_proj"], [1], ["layers"], True),  # expert 1, layer 1
+    ("model.layers.2.mlp.experts.1.up_proj", ["up_proj"], [1], ["layers"], False),  # layer 2, not 1
+    # MoE without explicit layers_pattern - should still match layer index, not expert index
+    ("model.layers.1.mlp.experts.0.up_proj", ["up_proj"], [1], None, True),
+    ("model.layers.1.mlp.experts.0.up_proj", ["up_proj"], [0], None, False),  # must not match expert 0
+    ("model.layers.2.mlp.experts.1.up_proj", ["up_proj"], [1], None, False),  # must not match expert 1
 ]
 
 MAYBE_INCLUDE_ALL_LINEAR_LAYERS_TEST_CASES = [