Allen had 10 disposals in the first quarter, 11 in the second and finished with 30 and 12 marks in a dominant display in the back half.
After a tight contest all day - in which the hosts led by seven, nine and 12 at each change - Queensland powered away with a six goals to two final term to win 15.9 (99) to 9.7 (63).
They dominated possession (368-254 disposals and 127-72 marks) and deserved the final margin of victory.
Allen ran without an opponent for much of the day and made the Territory pay, with his superb ball use setting up much of Queensland's good play.
National talent manager Kevin Sheehan was full of praise for the 18-year-old.
"His elite kicking was superb, just his use of the ball," Sheehan said.
"He showed he could take an overhead mark by standing on their shoulders in the first quarter and his work from setting up the game in the back half was super.
"He was the most influential player on the field."
Tom Fields, son of former Essendon player Neville, would be making Bombers fans happy with his continued good form in the carnival.
Fields had 27 disposals and 13 marks and his strong left boot was featured best with a 55m goal in the final term to put Queensland out of sight.
Midfielder Tom Overington worked hard for his 31 disposals.
For the Northern Territory, forward Gibson Turner almost was a standout in the first half, kicking three goals, and finishing with four for the match.
Turner led and jumped at the ball well for his eight marks and 12 disposals.
Gun midfielder Jed Anderson was kept quiet in the first quarter by Richard Newell but worked his way into the match with 15 disposals.
Queensland: 3.2 6.3 9.7 15.9 (99)
Northern Territory: 2.1 4.6 7.7 9.7 (61)
GOALS
Queensland: Cameron 2, Michael 2, Starcevich 2, Oxley 2, Thurlow 2, Boston, Davidson, Fields, Rolfe, Russ
Northern Territory: Turner 4, Collinson, Nundhirribala, Stokes, D.Williams, Tipungwuti
BEST
Queensland: Michael, Boston, Newell, Tucker, Fields, Overington, Allen
Northern Territory: Turner, Neade, Stokes, Wilson, Anderson, Stafford
Under-16s
Queensland 17.11 (113) defeated Northern Territory 9.13 (67)
GOALS
Queensland: Bourke 6, Mills 3, Davidson 3, Rokeby 2, Bisset, Selman, Conway
Northern Territory: McDonald 2, Rioli 1, McCauliffe 1, Simpson, McGarvie, Wasley-Black, Johanssen, Motlop
BEST
Queensland: Gribble, Bourke, Davidson, Rokeby, Conway, Tickner
Northern Territory: Ankers, Rioli, Waley-Black, Ross, Richardson, McCauliffe
