diff --git a/litellm/main.py b/litellm/main.py
index cb3ddc2f401..049f0ab07ce 100644
--- a/litellm/main.py
+++ b/litellm/main.py
@@ -3090,7 +3090,7 @@ def completion(  # type: ignore # noqa: PLR0915
                 print_verbose=print_verbose,
                 optional_params=optional_params,
                 litellm_params=litellm_params,
-                api_key=None,
+                api_key=api_key,
                 logger_fn=logger_fn,
                 encoding=_get_encoding(),
                 logging_obj=logging,
diff --git a/tests/litellm/llms/oobabooga/__init__.py b/tests/litellm/llms/oobabooga/__init__.py
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/tests/litellm/llms/oobabooga/test_oobabooga_api_key.py b/tests/litellm/llms/oobabooga/test_oobabooga_api_key.py
new file mode 100644
index 00000000000..1569c7b7173
--- /dev/null
+++ b/tests/litellm/llms/oobabooga/test_oobabooga_api_key.py
@@ -0,0 +1,94 @@
+"""
+Unit tests for the oobabooga provider — verify api_key is forwarded.
+
+Regression test for https://github.com/BerriAI/litellm/issues/21945
+"""
+
+import os
+import sys
+
+sys.path.insert(
+    0, os.path.abspath(os.path.join(os.path.dirname(__file__), "../../../.."))
+)
+
+from litellm.llms.oobabooga.chat.transformation import OobaboogaConfig
+
+
+def test_validate_environment_sets_auth_header_when_api_key_provided():
+    """api_key should produce an Authorization header."""
+    config = OobaboogaConfig()
+    headers = config.validate_environment(
+        headers={},
+        model="test-model",
+        messages=[{"role": "user", "content": "hi"}],
+        optional_params={},
+        litellm_params={},
+        api_key="my-secret-token",
+    )
+    assert headers["Authorization"] == "Token my-secret-token"
+
+
+def test_validate_environment_no_auth_header_when_api_key_none():
+    """When api_key is None, Authorization header should not be set."""
+    config = OobaboogaConfig()
+    headers = config.validate_environment(
+        headers={},
+        model="test-model",
+        messages=[{"role": "user", "content": "hi"}],
+        optional_params={},
+        litellm_params={},
+        api_key=None,
+    )
+    assert "Authorization" not in headers
+
+
+def test_oobabooga_completion_forwards_api_key_to_http_request():
+    """
+    Regression test for https://github.com/BerriAI/litellm/issues/21945
+
+    Verify that calling oobabooga.completion() with an api_key results
+    in an Authorization header being sent in the outgoing HTTP request.
+    """
+    from unittest.mock import MagicMock, patch
+
+    from litellm.llms.oobabooga.chat import oobabooga
+
+    mock_response = MagicMock()
+    mock_response.status_code = 200
+    mock_response.json.return_value = {
+        "choices": [{"message": {"content": "hello"}}],
+        "usage": {
+            "prompt_tokens": 1,
+            "completion_tokens": 1,
+            "total_tokens": 2,
+        },
+    }
+
+    mock_client = MagicMock()
+    mock_client.post.return_value = mock_response
+
+    with patch(
+        "litellm.llms.oobabooga.chat.oobabooga._get_httpx_client",
+        return_value=mock_client,
+    ):
+        from litellm.types.utils import ModelResponse
+
+        oobabooga.completion(
+            model="test-model",
+            messages=[{"role": "user", "content": "hi"}],
+            api_base="http://localhost:5000",
+            model_response=ModelResponse(),
+            print_verbose=lambda *a, **kw: None,
+            encoding=None,
+            api_key="my-secret-token",
+            logging_obj=MagicMock(),
+            optional_params={},
+            litellm_params={},
+        )
+
+    mock_client.post.assert_called_once()
+    call_kwargs = mock_client.post.call_args
+    headers = call_kwargs.kwargs.get("headers") or call_kwargs[1].get("headers", {})
+    assert headers.get("Authorization") == "Token my-secret-token", (
+        f"Expected Authorization header, got: {headers}"
+    )