John Plath is an Australian former rugby league footballer of the 1990s. He played in all of the Brisbane Broncos' first four grand final wins from the interchange bench and retired as the most-capped Bronco not to have played representative football.
His utility value saw him on the bench in the Broncos' inaugural grand final win in 1992. In the weeks following the grand final Plath travelled with the Broncos to England, where he played from the interchange bench in the 1992 World Club Challenge against British champions Wigan, helping Brisbane become the first NSWRL club to win the match in Britain. The following year he again played in the Broncos' grand final, helping them to a second consecutive premiership. He was a replacement player in Brisbane's 20-14 loss to Wigan in the 1994 World Club Challenge at Lang Park. Plath was also used from the bench in Brisbane's win over the Cronulla-Sutherland Sharks in the Broncos' Super League grand final for the 1997 Telstra Cup before keeping his big-game interchange reputation intact in a cameo role in the Broncos' 1998 NRL grand final win against the Canterbury Bulldogs.
After retiring from playing, Plath spent two years at Wynnum-Manly as a development officer and CEO.