The 2020–21 James Madison Dukes men's basketball team represented James Madison University in the 2020–21 NCAA Division I men's basketball season. The Dukes, led by first-year head coach Mark Byington, played their home games at the newly opened Atlantic Union Bank Center in Harrisonburg, Virginia as members of the Colonial Athletic Association (CAA). In a season limited due to the ongoing COVID-19 pandemic, they finished the season 13–7, 8–2 in CAA play, to earn a share of the regular-season championship. They lost in the quarterfinals of the CAA tournament to Elon.