diff --git a/packages/x-data-grid-pro/src/models/dataGridProProps.ts b/packages/x-data-grid-pro/src/models/dataGridProProps.ts
index e7425e47b4ac..af712a2c846d 100644
--- a/packages/x-data-grid-pro/src/models/dataGridProProps.ts
+++ b/packages/x-data-grid-pro/src/models/dataGridProProps.ts
@@ -167,7 +167,7 @@ export interface DataGridProPropsWithoutDefaultValue<R extends GridValidRowModel
    * @param {R} row The row from which we want the path.
    * @returns {string[]} The path to the row.
    */
-  getTreeDataPath?: (row: R) => string[];
+  getTreeDataPath?: (row: R) => ReadonlyArray<string>;
   /**
    * Callback fired when scrolling to the bottom of the grid viewport.
    * @param {GridRowScrollEndParams} params With all properties from [[GridRowScrollEndParams]].
diff --git a/packages/x-data-grid-pro/src/tests/treeData.DataGridPro.test.tsx b/packages/x-data-grid-pro/src/tests/treeData.DataGridPro.test.tsx
index c6b60ed1fd4f..7a41f87c1d09 100644
--- a/packages/x-data-grid-pro/src/tests/treeData.DataGridPro.test.tsx
+++ b/packages/x-data-grid-pro/src/tests/treeData.DataGridPro.test.tsx
@@ -214,7 +214,7 @@ describe('<DataGridPro /> - Tree data', () => {
       ]);
       setProps({
         getTreeDataPath: (row) => [...row.name.split('.').reverse()],
-      } as DataGridProProps);
+      } as Pick<DataGridProProps, 'getTreeDataPath'>);
       expect(getColumnValues(1)).to.deep.equal([
         'A',
         'A.A',