diff --git a/litellm/router.py b/litellm/router.py
index 5ffe60c2da0..59767843d6b 100644
--- a/litellm/router.py
+++ b/litellm/router.py
@@ -7357,6 +7357,7 @@ class Router:
         - None: If the deployment is not active for the current environment (if 'supported_environments' is set in litellm_params)
         """
         try:
+            _litellm_params = self._apply_xai_oauth_alias(_litellm_params)
             litellm_params: LiteLLM_Params = LiteLLM_Params(**_litellm_params)
             deployment = Deployment(
                 **deployment_info,
@@ -7831,9 +7832,49 @@ class Router:
         # deployments have been registered.
         self._finalize_adaptive_router_if_configured()
 
+    @staticmethod
+    def _normalize_xai_oauth_alias_model(model: str, custom_llm_provider: Optional[str]) -> Optional[str]:
+        """Map the ``xai-oauth`` / ``xai_oauth`` provider alias onto ``xai``.
+
+        xAI OAuth is enabled through the ``use_xai_oauth`` litellm param on an
+        ``xai/`` deployment, so ``xai-oauth`` is not a real provider. Users who
+        follow the ``litellm xai-oauth login`` CLI naming and configure the
+        provider as ``xai-oauth`` (as a model prefix or ``custom_llm_provider``)
+        would otherwise hit "Unsupported provider - xai-oauth". Returns the
+        normalized ``xai/<model>`` string, or None when no alias is present.
+        """
+        aliases = ("xai-oauth", "xai_oauth")
+        prefix = model.split("/", 1)[0] if "/" in model else None
+        if custom_llm_provider not in aliases and prefix not in aliases:
+            return None
+        bare_model = model.split("/", 1)[1] if prefix in (*aliases, "xai") else model
+        return f"xai/{bare_model}"
+
+    def _apply_xai_oauth_alias(self, litellm_params: dict) -> dict:
+        normalized_model = self._normalize_xai_oauth_alias_model(
+            litellm_params.get("model") or "",
+            litellm_params.get("custom_llm_provider"),
+        )
+        if normalized_model is None:
+            return litellm_params
+        return {
+            **{k: v for k, v in litellm_params.items() if k != "custom_llm_provider"},
+            "model": normalized_model,
+            "use_xai_oauth": True,
+        }
+
     def _add_deployment(self, deployment: Deployment) -> Deployment:
         import os
 
+        normalized_model = self._normalize_xai_oauth_alias_model(
+            deployment.litellm_params.model,
+            deployment.litellm_params.custom_llm_provider,
+        )
+        if normalized_model is not None:
+            deployment.litellm_params.model = normalized_model
+            deployment.litellm_params.custom_llm_provider = None
+            deployment.litellm_params.use_xai_oauth = True
+
         #### VALIDATE MODEL ########
         # Check if this is a prompt management model before validating as LLM provider
         litellm_model = deployment.litellm_params.model
diff --git a/tests/test_litellm/test_router.py b/tests/test_litellm/test_router.py
index 9c4d83ff7ea..350203007e1 100644
--- a/tests/test_litellm/test_router.py
+++ b/tests/test_litellm/test_router.py
@@ -1068,6 +1068,49 @@ def test_add_invalid_provider_to_router():
     assert router.pattern_router.patterns == {}
 
 
+@pytest.mark.parametrize(
+    "litellm_params",
+    [
+        {"model": "xai-oauth/grok-4.5"},
+        {"model": "xai_oauth/grok-4.5"},
+        {"model": "grok-4.5", "custom_llm_provider": "xai-oauth"},
+        {"model": "xai/grok-4.5", "custom_llm_provider": "xai_oauth"},
+        {"model": "xai-oauth/grok-4.5", "custom_llm_provider": "xai-oauth"},
+    ],
+)
+def test_router_normalizes_xai_oauth_alias(litellm_params):
+    """
+    Regression for https://github.com/BerriAI/litellm/issues/32660
+
+    xai-oauth is not a real provider; it is the xai provider with the
+    use_xai_oauth flag. Configuring the provider as xai-oauth (matching the
+    `litellm xai-oauth login` CLI) used to fail with
+    "Unsupported provider - xai-oauth". The router should transparently rewrite
+    it to xai/<model> with use_xai_oauth=True.
+    """
+    router = litellm.Router(
+        model_list=[{"model_name": "grok-4.5", "litellm_params": dict(litellm_params)}]
+    )
+
+    deployment = router.get_model_list()[0]["litellm_params"]
+    assert deployment["model"] == "xai/grok-4.5"
+    assert deployment.get("custom_llm_provider") is None
+    assert deployment["use_xai_oauth"] is True
+
+
+def test_router_leaves_plain_xai_deployment_untouched():
+    """A plain xai/ deployment must not have use_xai_oauth force-enabled."""
+    router = litellm.Router(
+        model_list=[
+            {"model_name": "grok-4.5", "litellm_params": {"model": "xai/grok-4.5"}}
+        ]
+    )
+
+    deployment = router.get_model_list()[0]["litellm_params"]
+    assert deployment["model"] == "xai/grok-4.5"
+    assert not deployment.get("use_xai_oauth")
+
+
 @pytest.mark.asyncio
 async def test_router_ageneric_api_call_with_fallbacks_helper():
     """