diff --git a/javascript/88-Merge-Sorted-Array.js b/javascript/88-Merge-Sorted-Array.js
new file mode 100644
index 000000000..f6b3ac58c
--- /dev/null
+++ b/javascript/88-Merge-Sorted-Array.js
@@ -0,0 +1,34 @@
+/**
+ * Linear 
+ * Time O(N) | Space O(1)
+ * https://leetcode.com/problems/merge-sorted-array/
+ * @param {number[]} nums1
+ * @param {number} m
+ * @param {number[]} nums2
+ * @param {number} n
+ * @return {void} Do not return anything, modify nums1 in-place instead.
+ */
+var merge = function(nums1, m, nums2, n) {
+
+    let k = m + n - 1;
+    m = m - 1;
+    n = n - 1;
+    while (m >= 0 && n >= 0) {
+        if (nums1[m] > nums2[n]) {
+            nums1[k] = nums1[m];
+            m--;
+        } else {
+            nums1[k] = nums2[n];
+            n--;
+        }
+        k--;
+    }
+
+    if (n >= 0) {
+        while (n >= 0) {
+            nums1[k] = nums2[n];
+            n--;
+            k--;
+        }
+    }
+};