The bass trumpet is a type of low trumpet which was first developed during the 1820s in Germany. It is usually pitched in 8' C or 9' B♭ today, but is sometimes built in E♭ and is treated as a transposing instrument sounding either an octave, a sixth or a ninth lower than written, depending on the pitch of the instrument. Although almost identical in length to the trombone, the bass trumpet possesses a tone which is harder and more metallic than that of the trombone. Although it has valves and the same tubing length as a trombone, the bass trumpet is very different from the valve trombone. Note that certain modern manufacturers offering 'tenor horns' in upright shape, 'valve trombones' and 'bass trumpets' are actually using the same valve cluster, bell, tubing and bell flare, just bent differently - in these cases the bass trumpet would be identical to the valve trombone.

The earliest mention of the bass trumpet is in the 1821 Allgemeine Musikalische Zeitung, in which Heinrich Stölzel's Chromatische Tenor-trompetenbaß and Griesling & Schlott's Chromatische Trompetenbaß are described. Several other variants were produced through the 1820s and were employed in military bands. Wide-bell versions in 9' B♭ are still used today in Austria and Bavaria under the name Baßtrompete, and narrow-bell versions in 9' B♭ are used in Italy under the name tromba bassa. They perform no melodic function, but are used solely to fill out harmonies.