diff --git a/src/plugins/es5.ts b/src/plugins/es5.ts
index 5d1030c7..99bd9d11 100644
--- a/src/plugins/es5.ts
+++ b/src/plugins/es5.ts
@@ -35,7 +35,7 @@ export const es5 = (): Plugin => {
           parser: {
             syntax: 'ecmascript',
           },
-          minify: this.options.minify ? {
+          minify: this.options.minify === true ? {
             compress: false,
             mangle: {
               reserved: this.options.globalName ? [this.options.globalName] : []