Gill Coliseum, Indoor sports arena at Oregon State University, United States

Gill Coliseum is a multi-purpose indoor arena on the Oregon State University campus in Corvallis, Oregon. It has tiered seating in orange and black around a light wood basketball court, a hanging video scoreboard, and a banner reading "OREGON STATE BEAVERS". The building also houses locker rooms, a weight room, and athletic department offices.

Gill Coliseum opened in December 1949 at a cost of $1.8 million, with an initial capacity of 10,000 and no seats obstructed by support pillars. It replaced the 2,500-seat Men's Gymnasium (now Langton Hall) as the venue for intercollegiate basketball. The name honors Amory "Slats" Gill, head coach from 1928 to 1964, though state rules initially barred naming a building after a living person, so the name was unofficial at first.

The south wall carries a painted mural of former Beavers players, among them Gary Payton, Brent Barry, A. C. Green, Lester Conner and Steve Johnson. The arena also hosts local events beyond sport, such as graduation ceremonies for surrounding high schools and religious services. The court itself is named for coach Ralph Miller, who led the basketball program from 1971 to 1989.

Gill Coliseum stands on the Oregon State University campus in Corvallis, at about 230 feet (70 m) above sea level. A $7 million renovation in 2009 brought the arena into compliance with the Americans with Disabilities Act and added new windows on the east and west sides. The Sports Performance Center, completed in spring 2008, sits between the coliseum and the Tommy Prothro Football Complex.

The south wall of Gill Coliseum carries a painted mural of former Oregon State players, among them Gary Payton, Brent Barry, A. C. Green, Lester Conner and Steve Johnson. The basement held the Horner Museum until it closed in 1995.