diff --git a/stubs/google-cloud-ndb/google/cloud/ndb/global_cache.pyi b/stubs/google-cloud-ndb/google/cloud/ndb/global_cache.pyi
index 976003bf9711..4811b9c67c01 100644
--- a/stubs/google-cloud-ndb/google/cloud/ndb/global_cache.pyi
+++ b/stubs/google-cloud-ndb/google/cloud/ndb/global_cache.pyi
@@ -1,5 +1,5 @@
 import abc
-from _typeshed import Incomplete
+from _typeshed import Incomplete, SupportsItems
 from typing_extensions import Self
 
 ConnectionError: Incomplete
@@ -14,6 +14,8 @@ class GlobalCache(metaclass=abc.ABCMeta):
     @abc.abstractmethod
     def set(self, items, expires=None): ...
     @abc.abstractmethod
+    def set_if_not_exists(self, items: SupportsItems[bytes, bytes | None], expires: float | None = None) -> dict[bytes, bool]: ...
+    @abc.abstractmethod
     def delete(self, keys): ...
     @abc.abstractmethod
     def watch(self, items): ...
@@ -29,6 +31,7 @@ class _InProcessGlobalCache(GlobalCache):
     def __init__(self) -> None: ...
     def get(self, keys): ...
     def set(self, items, expires=None) -> None: ...
+    def set_if_not_exists(self, items: SupportsItems[bytes, bytes | None], expires: float | None = None) -> dict[bytes, bool]: ...
     def delete(self, keys) -> None: ...
     def watch(self, items) -> None: ...
     def unwatch(self, keys) -> None: ...
@@ -47,6 +50,7 @@ class RedisCache(GlobalCache):
     def pipes(self): ...
     def get(self, keys): ...
     def set(self, items, expires=None) -> None: ...
+    def set_if_not_exists(self, items: SupportsItems[bytes, bytes | None], expires: float | None = None) -> dict[bytes, bool]: ...
     def delete(self, keys) -> None: ...
     def watch(self, items) -> None: ...
     def unwatch(self, keys) -> None: ...
@@ -70,6 +74,7 @@ class MemcacheCache(GlobalCache):
     def caskeys(self): ...
     def get(self, keys): ...
     def set(self, items, expires=None): ...
+    def set_if_not_exists(self, items: SupportsItems[bytes, bytes | None], expires: float | None = None) -> dict[bytes, bool]: ...
     def delete(self, keys) -> None: ...
     def watch(self, items) -> None: ...
     def unwatch(self, keys) -> None: ...