diff --git a/ext/herb/extconf.rb b/ext/herb/extconf.rb
index cb215e568..ac15be929 100644
--- a/ext/herb/extconf.rb
+++ b/ext/herb/extconf.rb
@@ -24,7 +24,8 @@
 $INCFLAGS << " -I#{prism_src_path}"
 $INCFLAGS << " -I#{prism_src_path}/util"
 
-$CFLAGS << " -DPRISM_EXPORT_SYMBOLS=static "
+$CFLAGS << " -DPRISM_EXPORT_SYMBOLS=static"
+$CFLAGS << " -fvisibility=hidden"
 
 herb_src_files = Dir.glob("#{$srcdir}/../../src/**/*.c").map { |file| file.delete_prefix("../../../../ext/herb/") }.sort
 
diff --git a/ext/herb/extension.c b/ext/herb/extension.c
index ea0ca7e63..dee8fec23 100644
--- a/ext/herb/extension.c
+++ b/ext/herb/extension.c
@@ -124,7 +124,7 @@ static VALUE Herb_version(VALUE self) {
   return rb_funcall(rb_mKernel, rb_intern("sprintf"), 4, format_string, gem_version, libprism_version, libherb_version);
 }
 
-void Init_herb(void) {
+__attribute__((visibility("default"))) void Init_herb(void) {
   mHerb = rb_define_module("Herb");
   cPosition = rb_define_class_under(mHerb, "Position", rb_cObject);
   cLocation = rb_define_class_under(mHerb, "Location", rb_cObject);