diff --git a/Data-Structures/Tree/AVLTree.js b/Data-Structures/Tree/AVLTree.js
index d2b34362c..1390defd3 100644
--- a/Data-Structures/Tree/AVLTree.js
+++ b/Data-Structures/Tree/AVLTree.js
@@ -90,14 +90,14 @@ const AVLTree = (function () {
   }
 
   // check if tree is balanced else balance it for insertion
-  const insertBalance = function (node, _val, balanceFactor) {
-    if (balanceFactor > 1 && _val < node._left._val) {
+  const insertBalance = function (node, _val, balanceFactor, tree) {
+    if (balanceFactor > 1 && tree._comp(_val, node._left._val) < 0) {
       return rightRotate(node) // Left Left Case
     }
-    if (balanceFactor < 1 && _val > node._right._val) {
+    if (balanceFactor < 1 && tree._comp(_val, node._right._val) > 0) {
       return leftRotate(node) // Right Right Case
     }
-    if (balanceFactor > 1 && _val > node._left._val) {
+    if (balanceFactor > 1 && tree._comp(_val, node._left._val) > 0) {
       node._left = leftRotate(node._left) // Left Right Case
       return rightRotate(node)
     }
@@ -140,7 +140,7 @@ const AVLTree = (function () {
     }
     updateHeight(root)
     const balanceFactor = getHeightDifference(root)
-    return isValidBalanceFactor(balanceFactor) ? root : insertBalance(root, val, balanceFactor)
+    return isValidBalanceFactor(balanceFactor) ? root : insertBalance(root, val, balanceFactor, tree)
   }
 
   // delete am element
diff --git a/Data-Structures/Tree/test/AVLTree.test.js b/Data-Structures/Tree/test/AVLTree.test.js
index 64cdd3ff4..f7ebc455e 100644
--- a/Data-Structures/Tree/test/AVLTree.test.js
+++ b/Data-Structures/Tree/test/AVLTree.test.js
@@ -5,26 +5,38 @@ describe('AVLTree Implementation: ', () => {
   const dataList = []
   const demoData = [1, 4, 6, 22, 7, 99, 4, 66, 77, 98]
 
+  const avlStringTree = new AVLTree()
+  const collator = new Intl.Collator()
+  const stringData = ['S', 'W', 'z', 'B', 'a']
+
   beforeAll(() => {
     demoData.forEach(item => {
       if (avlTree.add(item)) {
         dataList.push(item)
       }
     })
+
+    avlStringTree._comp = collator.compare
+    stringData.forEach(item => avlStringTree.add(item))
   })
 
   it('checks if element is inserted properly', () => {
     expect(dataList.length).toEqual(avlTree.size)
+    expect(stringData.length).toEqual(avlStringTree.size)
   })
 
   it('search if inserted element is present', () => {
     demoData.forEach(data => {
       expect(avlTree.find(data)).toBeTruthy()
     })
+    stringData.forEach(data => {
+      expect(avlStringTree.find(data)).toBeTruthy()
+    })
   })
 
   it('deletes the inserted element', () => {
     const deleteElement = dataList[3]
     expect(avlTree.remove(deleteElement)).toBeTruthy()
+    expect(avlStringTree.remove(stringData[3])).toBeTruthy()
   })
 })