diff --git a/metadock/yaml_utils.py b/metadock/yaml_utils.py
index 906ceed..9c853eb 100644
--- a/metadock/yaml_utils.py
+++ b/metadock/yaml_utils.py
@@ -1,3 +1,5 @@
+import operator
+from functools import reduce
 from typing import Any
 
 
@@ -18,7 +20,10 @@ def flatten_merge_keys(yaml_dict: Any) -> dict:
     for key in yaml_dict.keys():
         flat_yaml_value = flatten_merge_keys(yaml_dict[key])
         if key == "<<":
-            flattened_yaml_dict |= flat_yaml_value
+            if isinstance(flat_yaml_value, list):
+                flattened_yaml_dict |= reduce(operator.or_, flat_yaml_value, {})
+            elif isinstance(flat_yaml_value, dict):
+                flattened_yaml_dict |= flat_yaml_value
         else:
             flattened_yaml_dict[key] = flat_yaml_value
 
diff --git a/tests/test_yaml_utils.py b/tests/test_yaml_utils.py
index 127c99e..963302b 100644
--- a/tests/test_yaml_utils.py
+++ b/tests/test_yaml_utils.py
@@ -36,6 +36,16 @@
             {"key": "value", "inner": "item", "first": "level"},
             id="simple 2 level to flatten with adjacent key",
         ),
+        pytest.param(
+            {"<<": [{"key_a": "value"}, {"key_b": "value again"}], "first": "level"},
+            {"key_a": "value", "key_b": "value again", "first": "level"},
+            id="simple merge list",
+        ),
+        pytest.param(
+            {"<<": [{"k": "value"}, {"k": "value again"}], "first": "level"},
+            {"k": "value again", "first": "level"},
+            id="simple merge list with collision",
+        ),
     ],
 )
 def test_yaml_utils__flatten_merge_keys(yml_dict, flat_dict):