The men's welterweight boxing competition at the 2012 Olympic Games in London was held between 31 July and 12 August at the ExCeL Exhibition Centre.

Twenty-eight boxers from 28 nations competed.

The competition consisted of a single-elimination tournament.

Bronze medals were awarded to both semifinal losers.

Using video review, AIBA determined the bout referee gave too few cautions for holding fouls and should have awarded Spence at least four more points.