-Bubble sort is the simplest algorithm which compares two elements at a time and swaps them if they are in wrong order or if first element is greater than the second element. it repeatedly swaps elements until no swap is needed. -It is not normally used in practice except in School for the purpose of or to know how the sorting algorithm. -It is not much efficient sorting algorithm as others. -The complexity of Bubble Sort is О(n²) and it should not be used when n is large.