71-year-old Ferguson won 13 Premier League championships, two Champions League titles and five FA Cups among his 38 trophies. He has long been established as the most successful coach in British soccer history.
Manchester United does not have a successor in place, according to ESPN, and originally had planned to retire at the end of the 2001-02 season.
United won its most recent Premier League — the English league championship — title two weeks ago, giving the club a total of 20 all-time.
Ferguson has just two league matches left as head coach, before he moves into the roll of the club’s director and ambassador.