Daniel James O'Sullivan (born March 3, 1968) is an American former professional basketball player.

A 6′10″ (2.08 m), 250 lb (114 kg) center born in The Bronx, New York, O'Sullivan attended Fordham University.

He played with the Omaha Racers of the Continental Basketball Association,[1] and from the 1990–91 NBA season until 1996, he played with five different NBA teams: Utah Jazz (1990–91), New Jersey Nets (1992–93),[2] Milwaukee Bucks (1992–93), Detroit Pistons (1993–94) and Toronto Raptors (1995–96).

He has played for Washington Bullets during the 1993 pre-season (but not in the regular season).

He also played with Kinder Bologna, Teamsystem Bologna and Scavolini in the Italian league, and also in Greece for AEK (1999–2000).