diff --git a/include/grpc/impl/codegen/port_platform.h b/include/grpc/impl/codegen/port_platform.h
index ad1cd8594dd5eede0a8adc63436ce5a51f80d56d..30edbc7251f53bf947dff17663da5c86183a66a1 100644
--- a/include/grpc/impl/codegen/port_platform.h
+++ b/include/grpc/impl/codegen/port_platform.h
@@ -95,6 +95,7 @@
 #define GPR_WIN32 1
 #define GPR_GETPID_IN_PROCESS_H 1
 #define GPR_WINSOCK_SOCKET 1
+#define GPR_WINDOWS_SUBPROCESS 1
 #ifdef __GNUC__
 #define GPR_GCC_ATOMIC 1
 #define GPR_GCC_TLS 1