diff --git a/litellm/integrations/prometheus.py b/litellm/integrations/prometheus.py
index 163a66144af..f0f5d506eba 100644
--- a/litellm/integrations/prometheus.py
+++ b/litellm/integrations/prometheus.py
@@ -504,6 +504,11 @@ class PrometheusLogger(CustomLogger):
             "error_type",
             "hook_type",
         }
+        # Include dynamic custom labels so we don't warn on valid user-defined names.
+        known_labels.update(litellm.custom_prometheus_metadata_labels or [])
+        known_labels.update(
+            f"tag_{tag}" for tag in (litellm.custom_prometheus_tags or [])
+        )
         for name in raw_metrics:
             if name not in defined_metrics:
                 verbose_logger.warning(