After receiving the league trophy at half-time during Saturday's Championship match against Burnley, Alan McCormack's side were in action one final time against bottom of the table O's.
Forward Darcy Moffat scored a brace, plus goals from Jamie Odegah, Archie Heron and an own goal meant the young Hatters finished 12 points clear at the top of the table - scoring 84 goals in the process, conceding just 12.
A large amount of the squad have also been playing regularly for the U21s this season and Zack Nelson, Jayden Luker, Axel Piesold and Joe Johnson have been on the bench for the first team as well.
Under 18s squad:
Sam Bentley, Claude Kayibanda, Jack Lorentzen-Jones, Joe Johnson, Marcus Warren, Max Scott, Tyrell Giwa, Will Houghton, Archie Heron, Jayden Luker, Darcy Moffat, Axel Piesold, Jack Bateson, Jacob Pinnington, Jake Burger, Josh Odell-Bature, Millar Matthews-Lewis, Oliver Hemlin, Oli Lynch, Rio Martucci, Zack Nelson, Jacob Vickers and Jamie Odegah.