diff --git a/src/python/grpcio/grpc/_runtime_protos.py b/src/python/grpcio/grpc/_runtime_protos.py
index f4d08c437cb..625355c038f 100644
--- a/src/python/grpcio/grpc/_runtime_protos.py
+++ b/src/python/grpcio/grpc/_runtime_protos.py
@@ -51,6 +51,8 @@ def _interpreter_version_protos_and_services(*args, **kwargs):
 def protos(protobuf_path):  # pylint: disable=unused-argument
     """Returns a module generated by the indicated .proto file.
 
+    THIS IS AN EXPERIMENTAL API.
+
     Use this function to retrieve classes corresponding to message
     definitions in the .proto file.
 
@@ -72,6 +74,8 @@ def protos(protobuf_path):  # pylint: disable=unused-argument
 def services(protobuf_path):  # pylint: disable=unused-argument
     """Returns a module generated by the indicated .proto file.
 
+    THIS IS AN EXPERIMENTAL API.
+
     Use this function to retrieve classes and functions corresponding to
     service definitions in the .proto file, including both stub and servicer
     definitions.
@@ -94,6 +98,8 @@ def services(protobuf_path):  # pylint: disable=unused-argument
 def protos_and_services(protobuf_path):  # pylint: disable=unused-argument
     """Returns a 2-tuple of modules corresponding to protos and services.
 
+    THIS IS AN EXPERIMENTAL API.
+
     The return value of this function is equivalent to a call to protos and a
     call to services.
     """