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 20-year-old 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.”