diff --git a/litellm/litellm_core_utils/core_helpers.py b/litellm/litellm_core_utils/core_helpers.py
index 40592595a33..2462c282041 100644
--- a/litellm/litellm_core_utils/core_helpers.py
+++ b/litellm/litellm_core_utils/core_helpers.py
@@ -131,6 +131,9 @@ _FINISH_REASON_MAP: Final[dict[str, OpenAIChatCompletionFinishReason]] = {
     "content_filter": "content_filter",
     # Anthropic Sonnet 4
     "content_filtered": "content_filter",
+    # Generic error passthrough (OpenRouter and other OpenAI-compatible providers
+    # emit lowercase "error" when a provider fails mid-stream)
+    "error": "stop",
 }
 
 
diff --git a/tests/test_litellm/litellm_core_utils/test_core_helpers.py b/tests/test_litellm/litellm_core_utils/test_core_helpers.py
index b4f539da286..aa7f2990c13 100644
--- a/tests/test_litellm/litellm_core_utils/test_core_helpers.py
+++ b/tests/test_litellm/litellm_core_utils/test_core_helpers.py
@@ -192,6 +192,19 @@ class TestMapFinishReasonOpenAIPassthrough:
         assert map_finish_reason(reason) == reason
 
 
+class TestMapFinishReasonGenericError:
+    def test_lowercase_error_is_explicitly_mapped(self):
+        assert "error" in _FINISH_REASON_MAP
+        assert map_finish_reason("error") == "stop"
+
+    def test_lowercase_error_does_not_warn(self, mocker):
+        warn = mocker.patch(
+            "litellm.litellm_core_utils.core_helpers.verbose_logger.warning"
+        )
+        assert map_finish_reason("error") == "stop"
+        warn.assert_not_called()
+
+
 class TestMapFinishReasonUnknown:
     def test_unknown_value_defaults_to_stop(self):
         assert map_finish_reason("some_unknown_value") == "stop"