Original Adidas football polo Manchester United 2020/21

The 2020–21 season was Manchester United's 29th season in the Premier League and their 46th consecutive season in the top flight of English football. The club finished second in the Premier League, their joint-highest finish since the retirement of Sir Alex Ferguson in 2013, were knocked out of the EFL Cup in the semi-finals by local rivals Manchester City, in the quarter-finals of the FA Cup by Leicester City and finished third in their UEFA Champions League group, therefore being relegated to the UEFA Europa League.

The season threatened to be overshadowed by the attempted formation of a European Super League. On 18 April 2021, Manchester United announced they were joining 11 other European clubs as founding members of the Super League, a proposed 20-team competition intended to rival the UEFA Champions League. The announcement drew an unprecedented backlash from supporters, other clubs, media partners, sponsors, players and the UK Government, forcing the club to withdraw just two days later. The failure of the project led to the resignation of executive vice-chairman Ed Woodward, while resultant protests against Woodward and owners the Glazer family led to a pitch invasion ahead of a league match against Liverpool on 2 May 2021, which saw a Premier League game get postponed due to supporter protests for the first time in the competition's history.

On the pitch, United equalled the biggest win in Premier League history with a 9–0 victory against Southampton on 2 February 2021, but ended the season with defeat on penalties in the UEFA Europa League final against Villarreal, going four straight seasons without a trophy and one season away from equalling their worst trophy drought since the club was last relegated.