diff --git a/packages/react-json-tree/README.md b/packages/react-json-tree/README.md
index 6e802e5f..10b3e50f 100644
--- a/packages/react-json-tree/README.md
+++ b/packages/react-json-tree/README.md
@@ -146,6 +146,7 @@ Their full signatures are:
 - `isCustomNode: function(value)` - overrides the default object type detection and renders the value as a single value
 - `collectionLimit: number` - sets the number of nodes that will be rendered in a collection before rendering them in collapsed ranges
 - `keyPath: (string | number)[]` - overrides the initial key path for the root node (defaults to `[root]`)
+- `onExpand: function(data, level, keyPath)` - on expand callback
 
 ### Credits
 
diff --git a/packages/react-json-tree/src/JSONNestedNode.tsx b/packages/react-json-tree/src/JSONNestedNode.tsx
index e678af6c..0b1229f1 100644
--- a/packages/react-json-tree/src/JSONNestedNode.tsx
+++ b/packages/react-json-tree/src/JSONNestedNode.tsx
@@ -95,6 +95,7 @@ interface Props extends CircularPropsPassedThroughJSONNestedNode {
   nodeTypeIndicator: string;
   createItemString: (data: any, collectionLimit: number) => string;
   expandable: boolean;
+  onExpand?: (data: any, level: number, keyPath: any[]) => void;
 }
 
 interface State {
@@ -130,6 +131,7 @@ export default class JSONNestedNode extends React.Component<Props, State> {
     sortObjectKeys: PropTypes.oneOfType([PropTypes.func, PropTypes.bool]),
     isCircular: PropTypes.bool,
     expandable: PropTypes.bool,
+    onExpand: PropTypes.func
   };
 
   static defaultProps = {
@@ -234,6 +236,14 @@ export default class JSONNestedNode extends React.Component<Props, State> {
 
   handleClick = () => {
     if (this.props.expandable) {
+      if (this.props.onExpand && !this.state.expanded) {
+        const {
+          data,
+          level,
+          keyPath
+        } = this.props;
+        this.props.onExpand(data, level, keyPath);
+      }
       this.setState({ expanded: !this.state.expanded });
     }
   };
diff --git a/packages/react-json-tree/src/index.tsx b/packages/react-json-tree/src/index.tsx
index f5013b9f..1832d49c 100644
--- a/packages/react-json-tree/src/index.tsx
+++ b/packages/react-json-tree/src/index.tsx
@@ -20,6 +20,7 @@ interface Props extends CircularPropsPassedThroughJSONTree {
   data: any;
   theme?: Theme;
   invertTheme: boolean;
+  onExpand?: (data: any, level: number, keyPath: any[]) => void;
 }
 
 interface State {
diff --git a/packages/react-json-tree/src/types.ts b/packages/react-json-tree/src/types.ts
index 5d8e1f7c..15b31d8f 100644
--- a/packages/react-json-tree/src/types.ts
+++ b/packages/react-json-tree/src/types.ts
@@ -9,6 +9,7 @@ interface SharedCircularPropsPassedThroughJSONTree {
     expanded: boolean,
     expandable: boolean
   ) => React.ReactNode;
+  onExpand?: (data: any, level: number, keyPath: any[]) => void;
 }
 interface SharedCircularPropsProvidedByJSONTree
   extends SharedCircularPropsPassedThroughJSONTree {
@@ -43,6 +44,7 @@ interface JSONNestedNodeCircularPropsPassedThroughJSONTree {
   isCustomNode: (value: any) => boolean;
   collectionLimit: number;
   sortObjectKeys?: ((a: any, b: any) => number) | boolean;
+  onExpand?: (data: any, level: number, keyPath: any[]) => void;
 }
 export type CircularPropsPassedThroughJSONTree =
   SharedCircularPropsPassedThroughJSONTree &