Gregory John Brough (26 March 1951 – 9 March 2014) was an Australian long-distance freestyle swimmer of the 1960s and 1970s, who won a bronze medal in the 1500-metre freestyle at the 1968 Summer Olympics. In Mexico City, Brough finished behind the American world record-holder Mike Burton and his teammate John Kinsella. He also finished fourth in the 400-metre, also won by Burton. At the 1970 Commonwealth Games in Edinburgh, Brough won a bronze in the 400-metre behind fellow Australian Graham White.