diff --git a/ext/rbs_extension/main.c b/ext/rbs_extension/main.c
index 6408b8f58..a03c2a214 100644
--- a/ext/rbs_extension/main.c
+++ b/ext/rbs_extension/main.c
@@ -3,6 +3,9 @@
 void
 Init_rbs_extension(void)
 {
+#ifdef HAVE_RB_EXT_RACTOR_SAFE
+  rb_ext_ractor_safe(true);
+#endif  
   rbs__init_constants();
   rbs__init_location();
   rbs__init_parser();