diff --git a/litellm/llms/openai/chat/gpt_transformation.py b/litellm/llms/openai/chat/gpt_transformation.py
index 16fd042cb2f..d116e749e9a 100644
--- a/litellm/llms/openai/chat/gpt_transformation.py
+++ b/litellm/llms/openai/chat/gpt_transformation.py
@@ -175,6 +175,9 @@ class OpenAIGPTConfig(BaseLLMModelInfo, BaseConfig):
             model_specific_params.append(
                 "user"
             )  # user is not a param supported by all openai-compatible endpoints - e.g. azure ai
+
+        if litellm.utils.supports_reasoning(model=model, custom_llm_provider="openai") and not model.startswith("gpt-5-chat"):
+            model_specific_params.append("reasoning_effort")
         return base_params + model_specific_params
 
     def _map_openai_params(
diff --git a/litellm/types/utils.py b/litellm/types/utils.py
index 73f46bd2181..a4a03e20c85 100644
--- a/litellm/types/utils.py
+++ b/litellm/types/utils.py
@@ -162,6 +162,8 @@ class ProviderSpecificModelInfo(TypedDict, total=False):
     supports_none_reasoning_effort: bool | None
     supports_minimal_reasoning_effort: bool | None
     supports_low_reasoning_effort: bool | None
+    supports_medium_reasoning_effort: bool | None
+    supports_high_reasoning_effort: bool | None
     supports_xhigh_reasoning_effort: bool | None
     supports_max_reasoning_effort: bool | None
     supports_output_config: bool | None
diff --git a/litellm/utils.py b/litellm/utils.py
index 802dc151428..20b80d651b0 100644
--- a/litellm/utils.py
+++ b/litellm/utils.py
@@ -2722,6 +2722,20 @@ def supports_reasoning(model: str, custom_llm_provider: str | None = None) -> bo
     return _supports_factory(model=model, custom_llm_provider=custom_llm_provider, key="supports_reasoning")
 
 
+def supports_medium_reasoning_effort(model: str, custom_llm_provider: str | None = None) -> bool:
+    """
+    Check if the given model supports medium reasoning effort and return a boolean value.
+    """
+    return _supports_factory(model=model, custom_llm_provider=custom_llm_provider, key="supports_medium_reasoning_effort")
+
+
+def supports_high_reasoning_effort(model: str, custom_llm_provider: str | None = None) -> bool:
+    """
+    Check if the given model supports high reasoning effort and return a boolean value.
+    """
+    return _supports_factory(model=model, custom_llm_provider=custom_llm_provider, key="supports_high_reasoning_effort")
+
+
 def supports_native_structured_output(model: str, custom_llm_provider: str | None = None) -> bool:
     """
     Check if the given model supports native structured outputs and return a boolean value.
diff --git a/tests/test_litellm/test_reasoning_effort_config.py b/tests/test_litellm/test_reasoning_effort_config.py
new file mode 100644
index 00000000000..db1009868bf
--- /dev/null
+++ b/tests/test_litellm/test_reasoning_effort_config.py
@@ -0,0 +1,47 @@
+import pytest
+import litellm
+from litellm.llms.openai.chat.gpt_transformation import OpenAIGPTConfig
+from litellm.utils import (
+    supports_reasoning,
+    supports_medium_reasoning_effort,
+    supports_high_reasoning_effort,
+)
+
+
+def test_openai_gpt_config_supported_params_includes_reasoning_effort_when_supported():
+    config = OpenAIGPTConfig()
+    
+    litellm.register_model({
+        "custom-reasoning-model": {
+            "max_tokens": 4096,
+            "input_cost_per_token": 0.00001,
+            "output_cost_per_token": 0.00002,
+            "litellm_provider": "openai",
+            "mode": "chat",
+            "supports_reasoning": True,
+            "supports_medium_reasoning_effort": True,
+            "supports_high_reasoning_effort": True,
+        }
+    })
+    
+    supported_params = config.get_supported_openai_params(model="custom-reasoning-model")
+    assert "reasoning_effort" in supported_params
+    assert supports_reasoning("custom-reasoning-model", custom_llm_provider="openai") is True
+    assert supports_medium_reasoning_effort("custom-reasoning-model", custom_llm_provider="openai") is True
+    assert supports_high_reasoning_effort("custom-reasoning-model", custom_llm_provider="openai") is True
+
+
+def test_supports_medium_and_high_reasoning_effort_helpers():
+    litellm.register_model({
+        "plain-chat-model": {
+            "max_tokens": 4096,
+            "input_cost_per_token": 0.00001,
+            "output_cost_per_token": 0.00002,
+            "litellm_provider": "openai",
+            "mode": "chat",
+            "supports_reasoning": False,
+        }
+    })
+    
+    assert supports_medium_reasoning_effort("plain-chat-model", custom_llm_provider="openai") is False
+    assert supports_high_reasoning_effort("plain-chat-model", custom_llm_provider="openai") is False