diff --git a/src/agents/guardrail.py b/src/agents/guardrail.py
index a96f0f7d7..f8a272b53 100644
--- a/src/agents/guardrail.py
+++ b/src/agents/guardrail.py
@@ -241,7 +241,11 @@ async def my_async_guardrail(...): ...
     def decorator(
         f: _InputGuardrailFuncSync[TContext_co] | _InputGuardrailFuncAsync[TContext_co],
     ) -> InputGuardrail[TContext_co]:
-        return InputGuardrail(guardrail_function=f, name=name)
+        return InputGuardrail(
+            guardrail_function=f,
+            # If not set, guardrail name uses the function’s name by default.
+            name=name if name else f.__name__
+        )
 
     if func is not None:
         # Decorator was used without parentheses