diff --git a/src/php/ext/grpc/server.c b/src/php/ext/grpc/server.c
index adcc982e593e16c9b8b6ae67706e1f511da3a31a..6f8e1e4cd807203407e1d97dfdb33c5f2fa7640a 100644
--- a/src/php/ext/grpc/server.c
+++ b/src/php/ext/grpc/server.c
@@ -49,6 +49,7 @@
 
 #include <grpc/grpc.h>
 #include <grpc/grpc_security.h>
+#include <grpc/slice.h>
 
 #include "completion_queue.h"
 #include "server.h"