diff --git a/src/php/ext/grpc/php_grpc.c b/src/php/ext/grpc/php_grpc.c
index ec8a304df97..4fb34a8c879 100644
--- a/src/php/ext/grpc/php_grpc.c
+++ b/src/php/ext/grpc/php_grpc.c
@@ -26,6 +26,7 @@
 #include "call_credentials.h"
 #include "server_credentials.h"
 #include "completion_queue.h"
+#include <inttypes.h>
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>