diff --git a/litellm/llms/ollama/chat/transformation.py b/litellm/llms/ollama/chat/transformation.py
index 10bf3736e64..fb2acc94122 100644
--- a/litellm/llms/ollama/chat/transformation.py
+++ b/litellm/llms/ollama/chat/transformation.py
@@ -171,7 +171,7 @@ class OllamaChatConfig(BaseConfig):
                 if value.get("json_schema") and value["json_schema"].get("schema"):
                     optional_params["format"] = value["json_schema"]["schema"]
             if param == "reasoning_effort" and value is not None:
-                effort: Final = value.get("effort") if isinstance(value, dict) else value
+                effort: Final = value.get("effort") if isinstance(value, Mapping) else value
                 if effort is not None:
                     if model.startswith("gpt-oss"):
                         optional_params["think"] = effort
diff --git a/litellm/llms/ollama/completion/transformation.py b/litellm/llms/ollama/completion/transformation.py
index e8dfb209b19..7d2bb726f5a 100644
--- a/litellm/llms/ollama/completion/transformation.py
+++ b/litellm/llms/ollama/completion/transformation.py
@@ -1,6 +1,6 @@
 import json
 import time
-from collections.abc import AsyncIterator, Iterator
+from collections.abc import AsyncIterator, Iterator, Mapping
 from typing import TYPE_CHECKING, Any, Final
 
 from httpx._models import Headers, Response
@@ -215,7 +215,7 @@ class OllamaConfig(BaseConfig):
             elif param == "stop":
                 optional_params["stop"] = value
             elif param == "reasoning_effort" and value is not None:
-                effort: Final = value.get("effort") if isinstance(value, dict) else value
+                effort: Final = value.get("effort") if isinstance(value, Mapping) else value
                 if effort is not None:
                     if model.startswith("gpt-oss"):
                         optional_params["think"] = effort
diff --git a/tests/unit/llms/ollama/test_ollama_chat_transformation.py b/tests/unit/llms/ollama/test_ollama_chat_transformation.py
index 58595502357..d1a9fe6aaa8 100644
--- a/tests/unit/llms/ollama/test_ollama_chat_transformation.py
+++ b/tests/unit/llms/ollama/test_ollama_chat_transformation.py
@@ -1,6 +1,8 @@
 import inspect
 import os
 import sys
+from collections.abc import Mapping
+from types import MappingProxyType
 from typing import Final, cast
 
 import pytest
@@ -1000,11 +1002,12 @@ class TestOllamaChatReasoningEffort:
             ("none", False),
             ({"effort": "medium"}, True),
             ({"effort": "medium", "summary": "auto"}, True),
+            (MappingProxyType({"effort": "medium", "summary": "auto"}), True),
             ({"effort": "none", "summary": "detailed"}, False),
         ],
     )
     def test_reasoning_effort_string_or_dict_maps_to_think(
-        self, reasoning_effort: str | dict[str, str], expected_think: bool
+        self, reasoning_effort: str | Mapping[str, str], expected_think: bool
     ) -> None:
         optional_params: Final = get_optional_params(
             model="ollama_chat/qwen3:8b",
diff --git a/tests/unit/llms/ollama/test_ollama_completion_transformation.py b/tests/unit/llms/ollama/test_ollama_completion_transformation.py
index e51e5979deb..531cd190e3d 100644
--- a/tests/unit/llms/ollama/test_ollama_completion_transformation.py
+++ b/tests/unit/llms/ollama/test_ollama_completion_transformation.py
@@ -2,6 +2,8 @@ import base64
 import io
 import json
 import sys
+from collections.abc import Mapping
+from types import MappingProxyType
 from typing import Final
 from litellm._uuid import uuid
 from unittest.mock import MagicMock, patch
@@ -784,11 +786,12 @@ class TestOllamaConfigReasoningEffort:
         [
             ("medium", True),
             ({"effort": "medium", "summary": "auto"}, True),
+            (MappingProxyType({"effort": "medium", "summary": "auto"}), True),
             ({"effort": "none"}, False),
         ],
     )
     def test_reasoning_effort_string_or_dict_maps_to_think(
-        self, reasoning_effort: str | dict[str, str], expected_think: bool
+        self, reasoning_effort: str | Mapping[str, str], expected_think: bool
     ) -> None:
         optional_params: Final = OllamaConfig().map_openai_params(
             non_default_params={"reasoning_effort": reasoning_effort},