The men's triathlon was one of the triathlon events at the 2012 Summer Olympics in London, United Kingdom. It took place on 7 August 2012, featuring 55 men from 32 countries. It was the fourth appearance of an Olympic men's triathlon event since the first at the 2000 Olympics in Sydney. The race was around Hyde Park, a 1.42 km2 park in central London. The race was held over the "international distance" and consisted of 1.5 kilometres (0.93 mi) swimming, 42.959 kilometres (26.693 mi) road cycling, and 10 kilometres (6.2 mi) road running.

The triathlon events at the 2012 Summer Olympics were held in Hyde Park in London, United Kingdom, with the women's triathlon held on 4 August and the men's on 7 August. 110 triathletes from 39 countries competed with 55 men and 55 women competing. The races were held over the "international distance" and consisted of 1.5 kilometres (0.93 mi) swimming, 43 kilometres (27 mi) road cycling, and 10 kilometres (6.2 mi) road running.