diff --git a/litellm/proxy/_types.py b/litellm/proxy/_types.py
index b4f64a76fd1..30f24dcde7a 100644
--- a/litellm/proxy/_types.py
+++ b/litellm/proxy/_types.py
@@ -1,6 +1,6 @@
 import enum
 import json
-from datetime import datetime
+from datetime import datetime, timezone
 from typing import TYPE_CHECKING, Any, Callable, Dict, List, Literal, Optional, Union
 
 import httpx
@@ -803,6 +803,23 @@ class GenerateRequestBase(LiteLLMPydanticObjectBase):
     aliases: Optional[dict] = {}
     object_permission: Optional[LiteLLM_ObjectPermissionBase] = None
 
+    @model_validator(mode="after")
+    def validate_budget_reset_at(self) -> "GenerateRequestBase":
+        """Validate that budget_reset_at is not in the past"""
+        if self.budget_reset_at is not None:
+            # Ensure timezone-aware for comparison
+            reset_at = self.budget_reset_at
+            if reset_at.tzinfo is None:
+                reset_at = reset_at.replace(tzinfo=timezone.utc)
+
+            current_time = datetime.now(timezone.utc)
+            if reset_at < current_time:
+                raise ValueError(
+                    f"budget_reset_at cannot be in the past. "
+                    f"Provided: {reset_at.isoformat()}, Current time: {current_time.isoformat()}"
+                )
+        return self
+
 
 class AllowedVectorStoreIndexItem(LiteLLMPydanticObjectBase):
     index_name: str