The baritone horn, or sometimes just called baritone, is a low-pitched brass instrument. It is a piston-valve brass instrument with a predominantly cylindrical bore like the trumpet and uses a wide-rimmed cup mouthpiece like that of its peers the trombone and euphonium. Like the trombone and the euphonium, the baritone can be considered either a transposing or non-transposing instrument.

In the UK the baritone is frequently found in brass bands. The baritone horn in the United States is common in school and university bands, the baritones found in school inventories often being older models as the instrument over time is yielding in popularity to the euphonium.

A person who plays a baritone horn is a baritone (horn) player or baritonist.

Construction and general characteristics

The baritone, like the trombone and euphonium, is a nine-foot brass tube. Valves are most often piston-style. It is predominately of cylindrical bore, in contrast to the more conical bore of the euphonium, rendering its attack more distinct than the rounder attack of the euphonium.