The bass saxophone is one of the lowest-pitched members of the saxophone family—larger and lower than the more common baritone saxophone. It was likely the first type of saxophone built by Adolphe Sax, as first observed by Berlioz in 1842. It is a transposing instrument pitched in B♭, an octave below the tenor saxophone and a perfect fourth below the baritone saxophone. A bass saxophone in C, intended for orchestral use, was included in Adolphe Sax's patent, but few known examples were built. The bass saxophone is not a commonly used instrument, but it is heard on some 1920s jazz recordings, in free jazz, in saxophone choirs and sextets, and occasionally in concert bands and rock music.

The baritone saxophone is a member of the saxophone family of instruments, larger than the tenor saxophone, but smaller than the bass. It is the lowest-pitched saxophone in common use — the bass, contrabass and subcontrabass saxophones are relatively uncommon. Like all saxophones, it is a single-reed instrument. It is commonly used in concert bands, chamber music, military bands, big bands, and jazz combos. It can also be found in other ensembles such as rock bands and marching bands. Modern baritone saxophones are pitched in E♭.