The deal ends months of speculation about the future of the 23 year-old, who had been linked with a move away from Old Trafford during the latter stages of Jose Mourinho's ill-fated tenure at the club.
“I am loving my time at this club. From the day I joined I have been made to feel part of the United family and I have been incredibly humbled and overwhelmed by the warmth and love of our fans, who continue to amaze me with their support," Martial said via a statement. “I would like to thank Ole and his coaching staff for their belief in me and for helping me to take my game to the next level.
"This club is all about winning trophies and I am sure the next piece of silverware is not that far away.”