diff --git a/requirements-tests.txt b/requirements-tests.txt
index 57b8477f02d0..11107de60cd5 100644
--- a/requirements-tests.txt
+++ b/requirements-tests.txt
@@ -16,7 +16,7 @@ ruff==0.5.4              # must match .pre-commit-config.yaml
 aiohttp==3.10.2
 # grpc install only fails on Windows, but let's avoid building sdist on other platforms
 # https://github.com/grpc/grpc/issues/36201
-grpcio-tools; python_version < "3.13"
+grpcio-tools; python_version < "3.13" # For grpc_tools.protoc
 mypy-protobuf==3.6.0
 packaging==24.1
 pathspec>=0.11.1
diff --git a/scripts/sync_protobuf/google_protobuf.py b/scripts/sync_protobuf/google_protobuf.py
index ba9109008d54..818706431484 100644
--- a/scripts/sync_protobuf/google_protobuf.py
+++ b/scripts/sync_protobuf/google_protobuf.py
@@ -18,7 +18,7 @@
 
 # Whenever you update PACKAGE_VERSION here, version should be updated
 # in stubs/protobuf/METADATA.toml and vice-versa.
-PACKAGE_VERSION = "27.1"
+PACKAGE_VERSION = "28.2"
 
 STUBS_FOLDER = REPO_ROOT / "stubs" / "protobuf"
 ARCHIVE_FILENAME = f"protobuf-{PACKAGE_VERSION}.zip"
diff --git a/stubs/protobuf/METADATA.toml b/stubs/protobuf/METADATA.toml
index f08d51e7fcab..2a3e69f74eb2 100644
--- a/stubs/protobuf/METADATA.toml
+++ b/stubs/protobuf/METADATA.toml
@@ -1,8 +1,8 @@
 # Whenever you update version here, PACKAGE_VERSION should be updated
 # in scripts/sync_proto/google_protobuf.py and vice-versa.
-version = "5.27.*"
+version = "5.28.*"
 upstream_repository = "https://github.com/protocolbuffers/protobuf"
-extra_description = "Partially generated using [mypy-protobuf==3.6.0](https://github.com/nipunn1313/mypy-protobuf/tree/v3.6.0) and libprotoc 26.1 on [protobuf v27.1](https://github.com/protocolbuffers/protobuf/releases/tag/v27.1) (python `protobuf==5.27.1`)."
+extra_description = "Partially generated using [mypy-protobuf==3.6.0](https://github.com/nipunn1313/mypy-protobuf/tree/v3.6.0) and libprotoc 26.1 on [protobuf v28.2](https://github.com/protocolbuffers/protobuf/releases/tag/v28.2) (python `protobuf==5.28.2`)."
 partial_stub = true
 
 [tool.stubtest]
diff --git a/stubs/protobuf/google/protobuf/descriptor_pb2.pyi b/stubs/protobuf/google/protobuf/descriptor_pb2.pyi
index 020c3fcccb06..48d88f0b07e5 100644
--- a/stubs/protobuf/google/protobuf/descriptor_pb2.pyi
+++ b/stubs/protobuf/google/protobuf/descriptor_pb2.pyi
@@ -1304,12 +1304,13 @@ class FieldOptions(google.protobuf.message.Message):
     FEATURE_SUPPORT_FIELD_NUMBER: builtins.int
     UNINTERPRETED_OPTION_FIELD_NUMBER: builtins.int
     ctype: global___FieldOptions.CType.ValueType
-    """The ctype option instructs the C++ code generator to use a different
+    """NOTE: ctype is deprecated. Use `features.(pb.cpp).string_type` instead.
+    The ctype option instructs the C++ code generator to use a different
     representation of the field than it normally would.  See the specific
     options below.  This option is only implemented to support use of
     [ctype=CORD] and [ctype=STRING] (the default) on non-repeated fields of
-    type "bytes" in the open source release -- sorry, we'll try to include
-    other types in a future version!
+    type "bytes" in the open source release.
+    TODO: make ctype actually deprecated.
     """
     packed: builtins.bool
     """The packed option can be enabled for repeated primitive fields to enable
diff --git a/stubs/protobuf/google/protobuf/internal/well_known_types.pyi b/stubs/protobuf/google/protobuf/internal/well_known_types.pyi
index 6192d64ae19b..5013ea53fc03 100644
--- a/stubs/protobuf/google/protobuf/internal/well_known_types.pyi
+++ b/stubs/protobuf/google/protobuf/internal/well_known_types.pyi
@@ -73,7 +73,6 @@ _StructValueArg: TypeAlias = _StructValue | Mapping[str, _StructValueArg] | Sequ
 
 class Struct:
     def __getitem__(self, key: str) -> _StructValue: ...
-    def __contains__(self, item: object) -> bool: ...
     def __setitem__(self, key: str, value: _StructValueArg) -> None: ...
     def __delitem__(self, key: str) -> None: ...
     def __len__(self) -> int: ...