The 20 year-old made 36 appearances for Forest last season and was a key man in helping the Reds secure a playoff spot.
He told nottinghamforest.co.uk: "I was really pleased the way things went for me in the second half of the season and I'm delighted to have signed a new contract."
The Irishman joins Chris Doig and Des Walker who both recently signed new deals at the club.
