Prior to the 2012 Summer Olympics, none of the Laotian competitors qualified for the athletic events. Kilakone Siphonexay entered the Olympics with a personal best of 11.24 seconds. With his time, Siphonexay was exactly one second slower than the B standard qualifying time for the men's 100 m. On 4 August, Siphonexay finished sixth in the first preliminary heat with a time of 11.30 seconds. With his sixth place heat finish, Siphonexay was not one of the eight qualifiers that finished in the top two of the four heats. For the last two qualifying spots, Siphonexay did not reach the next round as he was not one of the two remaining athletes to have one of the top two fastest times. Overall, Siphonexay was 68th out of 75 competitors.