The 2003–04 Dayton Flyers men's basketball team represented the University of Dayton during the 2003–04 NCAA Division I men's basketball season. The Flyers, led by first year head coach Brian Gregory, played their home games at the University of Dayton Arena and were members of the Atlantic 10 Conference. They finished the season 24–9, 12–4 in A-10 play, finishing first in the A-10's West division. Dayton opened the season winning the Maui Invitational. The Flyers advanced to the finals of the Atlantic 10 tournament where they were defeated by rival Xavier. Dayton received an at-large bid to the NCAA tournament, the program's first consecutive NCAA appearances since the 1960s. The Flyers lost to DePaul in the first round.