The 2020–21 Army Black Knights men's basketball team represented the United States Military Academy during the 2020–21 NCAA Division I men's basketball season.

The Black Knights were led by fifth-year head coach Jimmy Allen, and played their home games at Christl Arena in West Point, New York as members of the Patriot League.

They earned the fourth seed in the Patriot League tournament, losing in the semifinals to Loyola.

The Black Knights finished the 2020–21 season with a record of 15–15, 10–8 in Patriot League play to finish in a tie for fourth place.

They lost in the quarterfinals of the Patriot League tournament to Lafayette.