diff --git a/docs/pages/x/api/tree-view/tree-view.json b/docs/pages/x/api/tree-view/tree-view.json
index ba89444fb66b..2d4f79111ff9 100644
--- a/docs/pages/x/api/tree-view/tree-view.json
+++ b/docs/pages/x/api/tree-view/tree-view.json
@@ -11,7 +11,10 @@
     },
     "defaultExpandIcon": { "type": { "name": "node" } },
     "defaultParentIcon": { "type": { "name": "node" } },
-    "defaultSelected": { "type": { "name": "any" }, "default": "[]" },
+    "defaultSelected": {
+      "type": { "name": "union", "description": "Array&lt;string&gt;<br>&#124;&nbsp;string" },
+      "default": "[]"
+    },
     "disabledItemsFocusable": { "type": { "name": "bool" } },
     "disableSelection": { "type": { "name": "bool" } },
     "expanded": { "type": { "name": "arrayOf", "description": "Array&lt;string&gt;" } },
diff --git a/packages/x-tree-view/src/TreeView/TreeView.tsx b/packages/x-tree-view/src/TreeView/TreeView.tsx
index cde3ba702c15..1e71a3d87831 100644
--- a/packages/x-tree-view/src/TreeView/TreeView.tsx
+++ b/packages/x-tree-view/src/TreeView/TreeView.tsx
@@ -159,7 +159,10 @@ TreeView.propTypes = {
    * When `multiSelect` is true this takes an array of strings; when false (default) a string.
    * @default []
    */
-  defaultSelected: PropTypes.any,
+  defaultSelected: PropTypes /* @typescript-to-proptypes-ignore */.oneOfType([
+    PropTypes.arrayOf(PropTypes.string),
+    PropTypes.string,
+  ]),
   /**
    * If `true`, will allow focus on disabled items.
    * @default false