NXT TakeOver: Vengeance Day was the 33rd NXT TakeOver and ninth Vengeance professional wrestling pay-per-view (PPV) and livestreaming event produced by WWE. It was held exclusively for wrestlers from the promotion's NXT brand division. The event took place on February 14, 2021, from the Capitol Wrestling Center, hosted at the WWE Performance Center in Orlando, Florida. The event revived WWE's old Vengeance PPV name, thus being the first Vengeance held since 2011. The event's name was also a play on Valentine's Day, as the event was held on the same day as the holiday. It was the first Vengeance to livestream on the WWE Network, as well as the final NXT TakeOver event and only Vengeance to air on the American version of the WWE Network before its merger under Peacock in March. It would also be the final Vengeance to air on PPV, as the following year's event was held as a television special, and while the 2023 event returned to livestreaming, NXT's major events as of the 2022 calendar year no longer air on PPV, just livestreaming.

Five matches were contested at the event. In the main event, Finn Bálor defeated Pete Dunne to retain the NXT Championship. In other prominent matches, MSK (Nash Carter and Wes Lee) defeated Grizzled Young Veterans (James Drake and Zack Gibson) to win the Men's Dusty Rhodes Tag Team Classic, while in the opening bout, Dakota Kai and Raquel González defeated Ember Moon and Shotzi Blackheart to win the inaugural Women's Dusty Rhodes Tag Team Classic. Vengeance Day also marked the WWE return of LA Knight, who previously performed as Slate Randall from 2013 to 2014 and was known as Eli Drake in Impact Wrestling.