diff --git a/ext/mbstring/tests/bug77165.phpt b/ext/mbstring/tests/bug77165.phpt
index 69708f613ab..5ad7584b16d 100644
--- a/ext/mbstring/tests/bug77165.phpt
+++ b/ext/mbstring/tests/bug77165.phpt
@@ -1,5 +1,7 @@
 --TEST--
 Bug #77165: mb_check_encoding crashes when argument given an empty array
+--SKIPIF--
+<?php require 'skipif.inc'; ?>
 --FILE--
 <?php
 var_dump(mb_check_encoding(array()));
diff --git a/ext/mbstring/tests/bug77454.phpt b/ext/mbstring/tests/bug77454.phpt
index b64452c79b7..74098580f15 100644
--- a/ext/mbstring/tests/bug77454.phpt
+++ b/ext/mbstring/tests/bug77454.phpt
@@ -1,5 +1,7 @@
 --TEST--
 Bug #77454: mb_scrub() silently truncates after a null byte
+--SKIPIF--
+<?php require 'skipif.inc'; ?>
 --FILE--
 <?php
 $str = "before\0after";
diff --git a/ext/mbstring/tests/internal_encoding.phpt b/ext/mbstring/tests/internal_encoding.phpt
index 3d097ac79c8..17f38d403ce 100644
--- a/ext/mbstring/tests/internal_encoding.phpt
+++ b/ext/mbstring/tests/internal_encoding.phpt
@@ -1,5 +1,7 @@
 --TEST--
 Check that "internal_encoding" ini is picked up by mbstring
+--SKIPIF--
+<?php require 'skipif.inc'; ?>
 --INI--
 internal_encoding=iso-8859-1
 --FILE--
diff --git a/ext/mbstring/tests/mb_convert_encoding_leak.phpt b/ext/mbstring/tests/mb_convert_encoding_leak.phpt
index 4e626b08949..47c0d33906e 100644
--- a/ext/mbstring/tests/mb_convert_encoding_leak.phpt
+++ b/ext/mbstring/tests/mb_convert_encoding_leak.phpt
@@ -1,5 +1,7 @@
 --TEST--
 mb_convert_encoding() shouldn't leak keys
+--SKIPIF--
+<?php require 'skipif.inc'; ?>
 --FILE--
 <?php