diff --git a/litellm/proxy/_types.py b/litellm/proxy/_types.py
index 98efadc10a8..aa50500e50d 100644
--- a/litellm/proxy/_types.py
+++ b/litellm/proxy/_types.py
@@ -2378,6 +2378,10 @@ class ConfigGeneralSettings(LiteLLMPydanticObjectBase):
         description="[DEPRECATED] Use 'user_header_mappings' instead. When set, the header value is treated as the end user id unless overridden by user_header_mappings.",
     )
     user_header_mappings: Optional[List[UserHeaderMapping]] = None
+    override_user_param: bool | None = Field(
+        None,
+        description="When True, the proxy overwrites any client-supplied 'user' param with the authenticated user id. Use when LiteLLM is the authentication boundary and clients must not be able to spoof 'user'.",
+    )
     supported_db_objects: Optional[List[SupportedDBObjectType]] = Field(
         None,
         description="Fine-grained control over which object types to load from the database when store_model_in_db is True. Available types: 'models', 'mcp', 'guardrails', 'vector_stores', 'pass_through_endpoints', 'prompts', 'model_cost_map', 'tools', 'config_overrides'. If not set, all objects are loaded (default behavior).",
diff --git a/litellm/proxy/litellm_pre_call_utils.py b/litellm/proxy/litellm_pre_call_utils.py
index a4cc4a62009..8ce0883beeb 100644
--- a/litellm/proxy/litellm_pre_call_utils.py
+++ b/litellm/proxy/litellm_pre_call_utils.py
@@ -1465,6 +1465,10 @@ async def add_litellm_data_to_request(
         if "user" not in data:
             data["user"] = user
 
+    if general_settings is not None and general_settings.get("override_user_param") is True:
+        if user_api_key_dict.user_id is not None:
+            data["user"] = user_api_key_dict.user_id
+
     if litellm.overwrite_user_with_key_hash is True:
         stampable_hash = _stampable_key_hash(user_api_key_dict)
         if stampable_hash is not None:
diff --git a/tests/test_litellm/proxy/test_litellm_pre_call_utils.py b/tests/test_litellm/proxy/test_litellm_pre_call_utils.py
index 1437899f561..c6f284b65bb 100644
--- a/tests/test_litellm/proxy/test_litellm_pre_call_utils.py
+++ b/tests/test_litellm/proxy/test_litellm_pre_call_utils.py
@@ -5421,3 +5421,54 @@ async def test_overwrite_user_with_key_hash_rejects_alias_without_marker(monkeyp
     )
 
     assert updated_data["user"] == "caller-chosen-id"
+
+
+@pytest.mark.asyncio
+async def test_override_user_param_clobbers_client_supplied_user():
+    user_api_key_dict = UserAPIKeyAuth(api_key="hashed-key", user_id="alice")
+    data = {"model": "gpt-4o", "user": "bob"}
+
+    updated_data = await add_litellm_data_to_request(
+        data=data,
+        request=_make_chat_request_mock(),
+        user_api_key_dict=user_api_key_dict,
+        proxy_config=MagicMock(),
+        general_settings={"override_user_param": True},
+        version="test-version",
+    )
+
+    assert updated_data["user"] == "alice"
+
+
+@pytest.mark.asyncio
+async def test_override_user_param_disabled_keeps_client_supplied_user():
+    user_api_key_dict = UserAPIKeyAuth(api_key="hashed-key", user_id="alice")
+    data = {"model": "gpt-4o", "user": "bob"}
+
+    updated_data = await add_litellm_data_to_request(
+        data=data,
+        request=_make_chat_request_mock(),
+        user_api_key_dict=user_api_key_dict,
+        proxy_config=MagicMock(),
+        general_settings={},
+        version="test-version",
+    )
+
+    assert updated_data["user"] == "bob"
+
+
+@pytest.mark.asyncio
+async def test_override_user_param_without_authenticated_user_id_keeps_client_value():
+    user_api_key_dict = UserAPIKeyAuth(api_key="hashed-key")
+    data = {"model": "gpt-4o", "user": "bob"}
+
+    updated_data = await add_litellm_data_to_request(
+        data=data,
+        request=_make_chat_request_mock(),
+        user_api_key_dict=user_api_key_dict,
+        proxy_config=MagicMock(),
+        general_settings={"override_user_param": True},
+        version="test-version",
+    )
+
+    assert updated_data["user"] == "bob"
diff --git a/ui/litellm-dashboard/src/lib/http/schema.d.ts b/ui/litellm-dashboard/src/lib/http/schema.d.ts
index 825d06d6a38..acbd2d1363a 100644
--- a/ui/litellm-dashboard/src/lib/http/schema.d.ts
+++ b/ui/litellm-dashboard/src/lib/http/schema.d.ts
@@ -22663,6 +22663,11 @@ export interface components {
              * @description [BETA] OpenTelemetry support - this might change, use with caution.
              */
             otel?: boolean | null;
+            /**
+             * Override User Param
+             * @description When True, the proxy overwrites any client-supplied 'user' param with the authenticated user id. Use when LiteLLM is the authentication boundary and clients must not be able to spoof 'user'.
+             */
+            override_user_param?: boolean | null;
             /**
              * Pass Through Endpoints
              * @description Set-up pass-through endpoints for provider-specific endpoints. Docs - https://docs.litellm.ai/docs/proxy/pass_through