diff --git a/composer.json b/composer.json
index 6f5e3e8c..899a3733 100644
--- a/composer.json
+++ b/composer.json
@@ -3,7 +3,8 @@
     "description": "Tolerant PHP-to-AST parser designed for IDE usage scenarios",
     "type": "library",
     "require": {
-        "php": ">=7.2"
+        "php": ">=7.2",
+        "ext-tokenizer": "*"
     },
     "require-dev": {
         "phpunit/phpunit": "^8.5.15",