diff --git a/ext/pcre/tests/locales.phpt b/ext/pcre/tests/locales.phpt
index 54f7f95050d..cb3028e2b5a 100644
--- a/ext/pcre/tests/locales.phpt
+++ b/ext/pcre/tests/locales.phpt
@@ -13,7 +13,7 @@ declare(encoding=latin1);
 setlocale(LC_ALL, 'C', 'POSIX');
 var_dump(preg_match('/^\w{6}$/', 'aאבחיט'));
 
-setlocale(LC_ALL, 'pt_PT', 'pt', 'portuguese');
+setlocale(LC_ALL, 'pt_PT', 'pt', 'pt_PT.ISO8859-1', 'portuguese');
 var_dump(preg_match('/^\w{6}$/', 'aאבחיט'));
 
 setlocale(LC_ALL, 'C', 'POSIX');