Brigitte McMahon is an athlete from Switzerland. She competes in triathlon.

McMahon competed at the first Olympic triathlon at the 2000 Summer Olympics. She won the gold medal with a total time of 2:00:40.52, which is still (as of 2005) the fastest time for a female in an Olympic triathlon. Her split times were 19:44.58 for the swim, 1:05:42.30 for the cyling and 0:35:13.64 for the run.