diff --git a/scala/21-Merge-Two-Sorted-Lists.scala b/scala/21-Merge-Two-Sorted-Lists.scala
new file mode 100644
index 000000000..8354a2834
--- /dev/null
+++ b/scala/21-Merge-Two-Sorted-Lists.scala
@@ -0,0 +1,34 @@
+/**
+ * Definition for singly-linked list.
+ * class ListNode(_x: Int = 0, _next: ListNode = null) {
+ *   var next: ListNode = _next
+ *   var x: Int = _x
+ * }
+ */
+object Solution {
+    def mergeTwoLists(list1: ListNode, list2: ListNode): ListNode = {
+        val head = new ListNode()
+        var tail = head
+        var (ptr1, ptr2) = (list1, list2)
+        
+        while (ptr1 != null && ptr2 != null) {
+            if (ptr1.x <= ptr2.x) {
+                tail.next = ptr1
+                ptr1 = ptr1.next
+            } else {
+                tail.next = ptr2
+                ptr2 = ptr2.next
+            }
+            
+            tail = tail.next
+        }
+        
+        if (ptr1 != null) {
+            tail.next = ptr1
+        } else if (ptr2 != null) {
+            tail.next = ptr2
+        }
+        
+        return head.next
+    }
+}
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