diff --git a/Dockerfile b/Dockerfile
index 2b99a6f..924f1fb 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -19,6 +19,7 @@ RUN apk update && \
     php5-mysql \
     php5-mysqli \
     php5-mcrypt \
+    php5-mbstring \
     php5-ctype \
     php5-zlib \
     php5-gd \