diff --git a/src/Mbstring/composer.json b/src/Mbstring/composer.json
index 4ed241a3..daa07f86 100644
--- a/src/Mbstring/composer.json
+++ b/src/Mbstring/composer.json
@@ -16,7 +16,8 @@
         }
     ],
     "require": {
-        "php": ">=7.2"
+        "php": ">=7.2",
+        "ext-iconv": "*"
     },
     "provide": {
         "ext-mbstring": "*"