Greenwood has become a mainstay in the Red Devils senior team under coach Ole Gunnar Solskjaer since making his debut in 2019.
The 19-year-old burst onto the scene last season, scoring 19 goals and providing five assists in 51 appearances in all competitions for United. He has played 82 games so far for his boyhood club.
Greenwood is touted as one of the brightest young players in English football and has been rewarded with a new deal due to his meteoric rise to prominence.
“When you join the club at seven years old, you just dream of playing for the first-team one day. I’ve worked so hard to reach this level and the last two years have been amazing. There is so much that I want to achieve in the game and I know that this is the perfect environment to play my football,” Greenwood said after extending his stay.
“With the support from the manager, his coaching staff and so many great players to learn from; I know that I am developing every single day. There is a lot more to come from myself and this team and I am so committed to working hard week in, week out to help the group achieve success.
“I want to repay the club for the support that everyone has given me over the years and show everyone just what I am capable of.