A brass quintet is a five-piece musical ensemble composed of brass instruments. The instrumentation for a brass quintet typically includes two trumpets or cornets, one French horn, one trombone or euphonium/baritone horn, and one tuba or bass trombone. Musicians in a brass quintet may often play multiple instruments. Trumpet players for instance may double on piccolo trumpets and flugelhorns. There can be variation in instrumentation depending on the type of quintet. In some quintets, the horn is replaced by an additional trombone. Euphonium may also be substituted for the trombone part. While the tuba is considered a standard, the range and style of many pieces lend themselves to being played with bass trombone as the lowest-pitched instrument. Additionally, some pieces call for the use of percussion instruments, particularly the snare drum, tambourine, or timpani.

A brass instrument is a musical instrument that produces sound by sympathetic vibration of air in a tubular resonator in sympathy with the vibration of the player's lips. Brass instruments are also called labrosones or labrophones, from Latin and Greek elements meaning 'lip' and 'sound'.