diff --git a/plugins/model-providers/upstage/__init__.py b/plugins/model-providers/upstage/__init__.py
index 7bc202d4bf6a..d36c0734a3a9 100644
--- a/plugins/model-providers/upstage/__init__.py
+++ b/plugins/model-providers/upstage/__init__.py
@@ -75,8 +75,8 @@ class UpstageProfile(ProviderProfile):
         if reasoning_config.get("enabled") is False:
             return {}, top_level
 
-        # Map Hermes' effort vocabulary onto Solar's accepted set. xhigh/max
-        # collapse to high (Solar's strongest). minimal → off (omit). An
+        # Map Hermes' effort vocabulary onto Solar's accepted set. xhigh/max/
+        # ultra collapse to high (Solar's strongest). minimal → off (omit). An
         # enabled request with no recognised effort uses the default effort.
         effort = (reasoning_config.get("effort") or "").strip().lower()
         mapped = {
@@ -86,6 +86,7 @@ class UpstageProfile(ProviderProfile):
             "high": "high",
             "xhigh": "high",
             "max": "high",
+            "ultra": "high",
         }.get(effort, _DEFAULT_REASONING_EFFORT)
 
         if mapped:
diff --git a/tests/plugins/model_providers/test_upstage_profile.py b/tests/plugins/model_providers/test_upstage_profile.py
index f37971f2f791..257900aed198 100644
--- a/tests/plugins/model_providers/test_upstage_profile.py
+++ b/tests/plugins/model_providers/test_upstage_profile.py
@@ -78,7 +78,7 @@ class TestUpstageReasoning:
         assert extra_body == {}
         assert top_level == {"reasoning_effort": effort}
 
-    @pytest.mark.parametrize("effort", ["xhigh", "max"])
+    @pytest.mark.parametrize("effort", ["xhigh", "max", "ultra"])
     def test_pro_strong_efforts_collapse_to_high(self, upstage_profile, effort):
         _, top_level = upstage_profile.build_api_kwargs_extras(
             reasoning_config={"enabled": True, "effort": effort}, model="solar-pro2"