diff --git a/InterviewQuestions/Diameter_of_a_binary_tree.cpp b/InterviewQuestions/Diameter_of_a_binary_tree.cpp
new file mode 100644
index 0000000..d85c9e2
--- /dev/null
+++ b/InterviewQuestions/Diameter_of_a_binary_tree.cpp
@@ -0,0 +1,59 @@
+#include <bits/stdc++.h> 
+using namespace std; 
+  
+/* Tree node structure used in the program */
+struct Node { 
+    int data; 
+    Node* left, *right; 
+}; 
+  
+/* Function to find height of a tree */
+int height(Node* root, int& ans) 
+{ 
+    if (root == NULL) 
+        return 0; 
+  
+    int left_height = height(root->left, ans); 
+  
+    int right_height = height(root->right, ans); 
+  
+    // update the answer, because diameter of a 
+    // tree is nothing but maximum value of 
+    // (left_height + right_height + 1) for each node 
+    ans = max(ans, 1 + left_height + right_height); 
+  
+    return 1 + max(left_height, right_height); 
+} 
+  
+/* Computes the diameter of binary tree with given root. */
+int diameter(Node* root) 
+{ 
+    if (root == NULL) 
+        return 0; 
+    int ans = INT_MIN; // This will store the final answer 
+    int height_of_tree = height(root, ans); 
+    return ans; 
+} 
+  
+struct Node* newNode(int data) 
+{ 
+    struct Node* node = new Node; 
+    node->data = data; 
+    node->left = node->right = NULL; 
+  
+    return (node); 
+} 
+  
+// Driver code 
+int main() 
+{ 
+    struct Node* root = newNode(1); 
+    root->left = newNode(2); 
+    root->right = newNode(3); 
+    root->left->left = newNode(4); 
+    root->left->right = newNode(5); 
+  
+    printf("Diameter is %d\n", diameter(root)); 
+  
+    return 0; 
+}