diff --git a/README.md b/README.md
index e4551089..824c675e 100644
--- a/README.md
+++ b/README.md
@@ -130,7 +130,7 @@ The OpenAPI spec allows you to define [enums](https://swagger.io/docs/specificat
 data model. By default, we convert these enums definitions to [TypeScript enums](https://www.typescriptlang.org/docs/handbook/enums.html).
 However, these enums are merged inside the namespace of the model, this is unsupported by Babel, [see docs](https://babeljs.io/docs/en/babel-plugin-transform-typescript#impartial-namespace-support).
 Because we also want to support projects that use Babel [@babel/plugin-transform-typescript](https://babeljs.io/docs/en/babel-plugin-transform-typescript),
-we offer the flag `--useOptions` to generate [union types](https://www.typescriptlang.org/docs/handbook/unions-and-intersections.html#union-types)
+we offer the flag `--useUnionTypes` to generate [union types](https://www.typescriptlang.org/docs/handbook/unions-and-intersections.html#union-types)
 instead of the traditional enums. The difference can be seen below:
 
 **Enums:**