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 musical ensemble, also known as a music group or musical group, is a group of people who perform instrumental and/or vocal music, with the ensemble typically known by a distinct name. Some music ensembles consist solely of instrumentalists, such as the jazz quartet or the orchestra. Other music ensembles consist solely of singers, such as choirs and doo-wop groups. In both popular music and classical music, there are ensembles in which both instrumentalists and singers perform, such as the rock band or the Baroque chamber group for basso continuo and one or more singers. In classical music, trios or quartets either blend the sounds of musical instrument families or group instruments from the same instrument family, such as string ensembles or wind ensembles. Some ensembles blend the sounds of a variety of instrument families, such as the orchestra, which uses a string section, brass instruments, woodwinds, and percussion instruments, or the concert band, which uses brass, woodwinds, and percussion.