Marriott, who has enjoyed loan spells at Carlisle, Colchester and Woking in his short career so far, becomes Hatters boss John Still’s first summer signing.
The forward made his Ipswich debut in the 2012/13 season having successfully come through their youth ranks.
Marriott, who could earn a longer deal at Kenilworth Road, told the club’s official website: “I’ve had two good seasons out on loan and learned a lot but now I’m ready to settle at a club where I’ve got a good chance to contribute to the team.
“I like to run in behind and threaten defences, hassle them and don’t give them a minute’s peace, and I like to score goals – that is my main target. I pride myself on goalscoring.”