The 2004 National AFL Under 18 Championships was the ninth edition of the AFL Under 18 Championships. Eight teams competed in the championships: Vic Metro, Vic Country, South Australia and Western Australia in Division 1, and New South Wales/Australian Capital Territory (NSW/ACT), Northern Territory, Queensland and Tasmania in Division 2. The competition was played over three rounds across two divisions. Vic Metro and the Northern Territory were the Division 1 and Division 2 champions, respectively. The Michael Larke Medal (for the best player in Division 1) was awarded to Victoria Metro's Jesse W. Smith, and the Hunter Harrison Medal (for the best player in Division 2) was won by the Northern Territory's Richard Tambling.