In the game of cricket, the square leg umpire is the second of the two on-field umpires.
While the main umpire stands behind the stumps at the bowler's end, the square leg umpire stands at square leg, around 25 metres from the batter. This position is ideal for adjudicating on stumpings and hit-wicket decisions, as well as any run-outs or running one short decisions that occur at the batter's end. Occasionally the square leg umpire is called upon to assist the main umpire in determining whether the ball bounced prior to a claimed catch, or to help in determining whether a shot is a four or a six.
But for the most part, the square leg umpire is able to relax a little more than the main umpire, whose duties are far more onerous. This relaxation does not last long however, as at the end of each over the square leg umpire becomes the main umpire, and vice versa.