Brian Janssen is an Australian professional light/light welter/welter/light middleweight boxer of the 1980s who won the Queensland State light welterweight title, Australian light welterweight title, Australian welterweight title, and Commonwealth welterweight title, his professional fighting weight varied from 135 lb, id est (that is) lightweight to 148 3⁄4 lb, id est (that is) light middleweight.