diff --git a/src/openai/_models.py b/src/openai/_models.py
index ed4c1f82d6..709b855e19 100644
--- a/src/openai/_models.py
+++ b/src/openai/_models.py
@@ -657,7 +657,11 @@ def construct_type(*, value: object, type_: object, metadata: Optional[List[Any]
         if not is_mapping(value):
             return value
 
-        _, items_type = get_args(type_)  # Dict[_, items_type]
+        args = get_args(type_)
+        if len(args) < 2:
+            return value
+
+        _, items_type = args  # Dict[_, items_type]
         return {key: construct_type(value=item, type_=items_type) for key, item in value.items()}
 
     if (
diff --git a/src/openai/_utils/_transform.py b/src/openai/_utils/_transform.py
index 414f38c340..575c609cc2 100644
--- a/src/openai/_utils/_transform.py
+++ b/src/openai/_utils/_transform.py
@@ -180,7 +180,11 @@ def _transform_recursive(
         return _transform_typeddict(data, stripped_type)
 
     if origin == dict and is_mapping(data):
-        items_type = get_args(stripped_type)[1]
+        args = get_args(stripped_type)
+        if len(args) < 2:
+            return cast(object, data)
+
+        items_type = args[1]
         return {key: _transform_recursive(value, annotation=items_type) for key, value in data.items()}
 
     if (
@@ -346,7 +350,11 @@ async def _async_transform_recursive(
         return await _async_transform_typeddict(data, stripped_type)
 
     if origin == dict and is_mapping(data):
-        items_type = get_args(stripped_type)[1]
+        args = get_args(stripped_type)
+        if len(args) < 2:
+            return cast(object, data)
+
+        items_type = args[1]
         return {key: _transform_recursive(value, annotation=items_type) for key, value in data.items()}
 
     if (
diff --git a/tests/test_models.py b/tests/test_models.py
index cc204bac1d..49b5fe6b6a 100644
--- a/tests/test_models.py
+++ b/tests/test_models.py
@@ -133,6 +133,12 @@ class NestedModel(BaseModel):
     assert cast(Any, m.nested) is False
 
 
+def test_bare_dictionary_annotation() -> None:
+    value = {"hello": "world"}
+
+    assert construct_type(value=value, type_=dict) is value
+
+
 def test_nested_dictionary_model() -> None:
     class NestedModel(BaseModel):
         nested: Dict[str, BasicModel]
diff --git a/tests/test_transform.py b/tests/test_transform.py
index bece75dfc7..302982f1f2 100644
--- a/tests/test_transform.py
+++ b/tests/test_transform.py
@@ -161,6 +161,18 @@ async def test_ignores_invalid_input(use_async: bool) -> None:
     assert await transform({"foo": "<foo>"}, Foo7, use_async) == {"foo": "<foo>"}
 
 
+class BareDictTypedDict(TypedDict, total=False):
+    metadata: dict
+
+
+@parametrize
+@pytest.mark.asyncio
+async def test_bare_dict_annotation(use_async: bool) -> None:
+    data = {"metadata": {"hello": "world"}}
+
+    assert await transform(data, BareDictTypedDict, use_async) == data
+
+
 class DatetimeDict(TypedDict, total=False):
     foo: Annotated[datetime, PropertyInfo(format="iso8601")]