diff --git a/src/types.ts b/src/types.ts
index 08fe3376..8d030195 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -108,7 +108,7 @@ export interface IAceOptions {
   useSoftTabs?: boolean;
   tabSize?: number;
   wrap?: boolean;
-  foldStyle?: boolean;
+  foldStyle?: "markbegin" | "markbeginend" | "manual";
   /** path to a mode e.g "ace/mode/text" */
   mode?: string;
   /** on by default */
diff --git a/types.d.ts b/types.d.ts
index fbb78606..c0bd485f 100644
--- a/types.d.ts
+++ b/types.d.ts
@@ -84,7 +84,7 @@ export interface AceOptions {
     useSoftTabs?: boolean
     tabSize?: number
     wrap?: boolean
-    foldStyle?: boolean
+    foldStyle?: "markbegin"|"markbeginend"|"manual"
     /** path to a mode e.g "ace/mode/text" */
     mode?: string
     /** on by default */