diff --git a/.changeset/fix-react-tree-expanded.md b/.changeset/fix-react-tree-expanded.md
new file mode 100644
index 00000000000..be2c997d82a
--- /dev/null
+++ b/.changeset/fix-react-tree-expanded.md
@@ -0,0 +1,8 @@
+---
+'@siemens/ix-react': major
+---
+
+Correct the `onNodeToggled` event payload type by renaming `isExpaned` to `isExpanded`.
+
+Update event handlers to access `event.detail.isExpanded` instead of
+`event.detail.isExpaned`.
diff --git a/packages/react/src/tree/internal-tree.tsx b/packages/react/src/tree/internal-tree.tsx
index d43746111b3..3991debb1ff 100644
--- a/packages/react/src/tree/internal-tree.tsx
+++ b/packages/react/src/tree/internal-tree.tsx
@@ -24,7 +24,7 @@ import React from 'react';
 
 type IxTreeEvents = {
   onContextChange: EventName<IxTreeCustomEvent<TreeContext>>;
-  onNodeToggled: EventName<CustomEvent<{ id: string; isExpaned: boolean }>>;
+  onNodeToggled: EventName<CustomEvent<{ id: string; isExpanded: boolean }>>;
   onNodeClicked: EventName<CustomEvent<string>>;
   onNodeRemoved: EventName<CustomEvent<any>>;
 };
diff --git a/packages/react/src/tree/tree.tsx b/packages/react/src/tree/tree.tsx
index 96cfd3aeede..10ee00766f9 100644
--- a/packages/react/src/tree/tree.tsx
+++ b/packages/react/src/tree/tree.tsx
@@ -25,7 +25,7 @@ export type IxTreeProps = Omit<
   renderItem?: (data: any) => React.ReactNode;
   onContextChange?: (event: IxTreeCustomEvent<TreeContext>) => void;
   onNodeToggled?: (
-    event: CustomEvent<{ id: string; isExpaned: boolean }>
+    event: CustomEvent<{ id: string; isExpanded: boolean }>
   ) => void;
   onNodeClicked?: (event: CustomEvent<string>) => void;
   onNodeRemoved?: (event: CustomEvent<any>) => void;