diff --git a/dart/single_number.dart b/dart/single_number.dart
new file mode 100644
index 0000000..dd0525e
--- /dev/null
+++ b/dart/single_number.dart
@@ -0,0 +1,17 @@
+/*
+Given a non-empty array of integers nums, every element appears twice except for one. Find that single one.
+
+You must implement a solution with a linear runtime complexity and use only constant extra space.
+*/
+
+class Solution {
+  int singleNumber(List<int> nums) {
+    int ans = 0;
+
+    for (final int num in nums) {
+      ans ^= num;
+    }
+
+    return ans;
+  }
+}