diff --git a/bangdori/Third Maximum Number.js b/bangdori/Third Maximum Number.js
new file mode 100644
index 0000000..6510f17
--- /dev/null
+++ b/bangdori/Third Maximum Number.js	
@@ -0,0 +1,14 @@
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var thirdMax = function (nums) {
+  const sortedNums = nums.sort((a, b) => b - a);
+  const uniqueNums = [...new Set(sortedNums)];
+
+  if (uniqueNums.length <= 2) {
+    return uniqueNums[0];
+  }
+
+  return uniqueNums[2];
+};