diff --git a/src/php/ext/grpc/php7_wrapper.h b/src/php/ext/grpc/php7_wrapper.h
index fd8d35636f09ab7f3e139272277fbf5fe9da1648..0d40e8250736de4c9124c9b22c487273f7466e0b 100644
--- a/src/php/ext/grpc/php7_wrapper.h
+++ b/src/php/ext/grpc/php7_wrapper.h
@@ -143,7 +143,7 @@ static inline int php_grpc_zend_hash_find(HashTable *ht, char *key, int len,
 
 #define PHP_GRPC_RETURN_STRING(val, dup) RETURN_STRING(val)
 #define PHP_GRPC_MAKE_STD_ZVAL(pzv) \
-  zval _stack_zval_##pzv; \
+  static zval _stack_zval_##pzv; \
   pzv = &(_stack_zval_##pzv)
 #define PHP_GRPC_DELREF(zv)