Johann Christoph Denner invented the clarinet in Germany around the beginning of the 18th century. By adding a register key to a folk instrument called the chalumeau, Denner was able to extend the range of the instrument significantly. Over time, additional keywork and airtight pads were added to the clarinet to improve tone and playability. It has a single-reed mouthpiece, a straight cylindrical tube with an almost cylindrical bore, and a flared bell.

During the late baroque era, composers such as Bach and Handel were making new demands on the skills of their trumpeters, who were often required to play difficult melodic passages in the high, or as it came to be called, clarion register. Since the trumpets of this time had no valves or pistons, melodic passages would often require the use of the highest part of the trumpet's range, where the harmonics were close enough together to produce scales of adjacent notes as opposed to the gapped scales or arpeggios of the lower register. The trumpet parts that required this speciality were known by the term clarino and this in turn came to apply to the musicians themselves. It is probable that the term clarinet may stem from the diminutive version of the 'clarion' or 'clarino' and it has been suggested that clarino players may have helped themselves out by playing particularly difficult passages on these newly developed "mock trumpets".

Today, the clarinet is used in both jazz and classical ensembles, as well as in chamber groups, folk music, and as a solo instrument.