Which of the sorting algorithms has the lowest worst-case complexity?

The sorting algorithm with the lowest worst-case time complexity is Merge Sort, which operates at O(n log n). This efficiency applies regardless of the input data's initial order, making it a reliable choice for large datasets. Other algorithms, such as Quick Sort and Heap Sort, also have O(n log n) worst-case complexity, but Merge Sort is particularly noteworthy for its stable sorting properties.