QuickSort is a highly efficient sorting algorithm that uses a divide-and-conquer approach to sort elements in an array. It works by selecting a 'pivot' element and partitioning the other elements into two sub-arrays: those less than the pivot and those greater than the pivot. This process is recursively applied to the sub-arrays until the entire array is sorted. One of the key advantages of QuickSort is its average-case time complexity of O(n log n), making it faster than many other sorting algorithms like Bubble Sort and Insertion Sort. However, its worst-case time complexity is O(n²), which can occur when the smallest or largest element is consistently chosen as the pivot.