diff --git a/crates/oxc_napi/index.d.ts b/crates/oxc_napi/index.d.ts
index 6c0ed0531..57121f214 100644
--- a/crates/oxc_napi/index.d.ts
+++ b/crates/oxc_napi/index.d.ts
@@ -9,7 +9,7 @@
  * <https://github.com/babel/babel/blob/main/packages/babel-parser/typings/babel-parser.d.ts>
  */
 export interface ParserOptions {
-  sourceType?: string
+  sourceType?: 'script' | 'module' | 'unambiguous' | undefined
   sourceFilename?: string
 }
 export interface ParseResult {
diff --git a/crates/oxc_napi/src/lib.rs b/crates/oxc_napi/src/lib.rs
index 8fd56c226..d3ef716c6 100644
--- a/crates/oxc_napi/src/lib.rs
+++ b/crates/oxc_napi/src/lib.rs
@@ -15,7 +15,8 @@ use oxc_span::SourceType;
 #[napi(object)]
 #[derive(Default)]
 pub struct ParserOptions {
-    pub source_type: Option<String>, // "script" | "module" | "unambiguous";
+    #[napi(ts_type = "'script' | 'module' | 'unambiguous' | undefined")]
+    pub source_type: Option<String>,
     pub source_filename: Option<String>,
 }