diff --git a/alpine/5/Dockerfile b/alpine/5/Dockerfile
index d66a086..ae59378 100644
--- a/alpine/5/Dockerfile
+++ b/alpine/5/Dockerfile
@@ -31,7 +31,7 @@ FROM php:${PHP_VERSION}-fpm-alpine${ALPINE_VERSION} AS phpbuild
 
 LABEL maintainer="David Bomba <turbo124@gmail.com>"
 
-ARG php_require="bcmath gd pdo_mysql zip"
+ARG php_require="bcmath gd pdo_mysql zip mbstring"
 ARG php_suggest="exif imagick intl pcntl soap"
 ARG php_extra="opcache"