Sound Horizon has eighteen albums and twelve singles; nine of the albums are story albums and six of the singles are story maxis. The other albums and singles consist of collaborations, soundtracks, or image albums for other creative works, produced early in the band's history.
Since the 4th Story CD Elysion in 2005, the band has performed each of its story albums live. Great Territorial Expansion concerts gather band members to perform songs from previous works, sometimes in different arrangements.
Sound Horizon has had many performers, from vocalists and musicians to dancers and production staff.
Sound Horizon features many characters, some of whom appear in multiple works.