The Gepp Gym is a multi-purpose room which was given its current name in March 2001. It was named after Hall of Fame member and former athletic director Stephen Gepp. It is accessible from the Main Corridor, as well as the main entrance and from outside. All home basketball games are played in the gym, and all school plays (Fall Dramas and Spring Musicals) are performed there. It is filled to capacity during the Almost Anything Goes competition in March. Grade school productions and events are also performed there on occasion.
In an elevated section at the west end of the gym is the Senior Lounge, which contains two sound booths. The Senior Lounge is only accessible from the main entrance. The Pit is the section of the bleachers below the Senior Lounge, while there are two much larger sections of the bleachers on either side of it. Additionally, there is a large closet behind the Pit. The stage is on the gym's east side, and the Weight Room is accessible from a stairway on the southeast side.