diff --git a/Dockerfile b/Dockerfile
index 19bd309..8d88994 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -40,6 +40,7 @@ RUN \
     php${PHP_VERSION}-cli \
     php${PHP_VERSION}-common \
     php${PHP_VERSION}-curl \
+    php${PHP_VERSION}-mbstring \
     php${PHP_VERSION}-mysql \
     php${PHP_VERSION}-sqlite3 \
     php${PHP_VERSION}-xml \