A family of free-reed instruments, similar to the accordion but distinguished by typically having buttons on both ends which travel in the same direction as the bellows (whereas accordion buttons travel perpendicular to the direction of the bellows).

Sir Charles Wheatstone patented the English concertina in 1829. It is a chromatic instrument, typically hexagonal in shape, able to play all full and halftones needed for playing classical music. The English concertina is unisonoric (the same tone on push and on pull). Since it is relatively quiet, this instrument has not been played so often in orchestras as other instruments.

In 1834, Carl Friedrich Uhlig invented the German concertina. The instrument had a square form, five buttons on each side and was bisonoric. It was the predecessor to the bandoneón. Like all concertinas, it had just single tones on the left and right side, no buttons for chords and no bass action. Uhlig later started to build hexagonal instruments with 10 buttons on each side, bisonoric and tunes in C/G.

The German-Anglo concertina, or Anglo for short, was developed in 1850 by George Jones. He combined elements of the German and English concertinas and also extended the instrument with a 3rd row of accidentals and additional redundant tones. This made it possible to play fully chromatic on this originally diatonic instrument, even with some limitations (some tones are only available on push, others only on pull).

In the late 19th century and in the beginning of the 20th, the concertina became more and more widespread. It was small, light, relatively cheap and could been taken anywhere and so was played by travelling musicans, sailors and the Salvation Army.

The Anglo concertina has had a revival in the folk music scene, especially for playing Irish folk music, where diatonic accordions are also very popular.

Today concertinas with 20 or 30 buttons are being built. Rarely, models with 40 buttons or custom made types are found.