Geoff Southby (born 27 October 1950) is a former Australian rules footballer in the (then) Victorian Football League (VFL). An attacking full-back who ran hard from defence and stopped the best full-forwards, Southby was a key contributor to Carlton Football Club's success in the 1970s. In 2000, Southby was inducted into the Australian Football Hall of Fame. Southby was also inducted into the Carlton Football Club Hall of Fame, and he was elevated to Legend status in 2013. He his considered one of the best full-backs in VFL/AFL history.