Rashford signs new five-year Man Utd deal
The 25-year-old England forward, whose existing deal was due to expire next year, rose through the Old Trafford youth set-up and has scored 123 goals in 359 first-team appearances.
"I joined Manchester United as a seven-year-old boy with a dream," said Rashford in a club statement.
"That same passion, pride and determination to succeed still drives me every time I have the honour of wearing the shirt.
"I've already had some amazing experiences at this incredible club, but there is still a lot more to achieve and I remain relentlessly determined to win more trophies in the years ahead."
He added: "As a United fan all my life, I know the responsibility that comes with representing this badge and feel the highs and lows as much as anyone.
"I can assure you that I will give everything to help the team reach the level we are capable of and I can feel the same determination around the dressing room.
"I couldn't be more excited for the future under this manager."
Rashford broke the 30-goal barrier for the first time in his United career last season under Erik ten Hag as the club lifted the League Cup to end a six-year trophy drought.
Manchester United football director John Murtough said of Rashford's new deal, which expires on June 30, 2028: "Ever since he joined our academy 18 years ago, Marcus has epitomised what it takes to succeed as a Manchester United player.
"He is a brilliant talent but also humble, dedicated and driven.
"As he enters his prime years, we know there is still so much more to come from him and we can see the hunger that Marcus feels to achieve the highest levels of success here at Manchester United.
"Working with Erik ten Hag and his coaches is the perfect environment for Marcus to continue to develop into one of the best attacking players in the world."