The accordion is a musical instrument popular in Europe. It uses valves and keys to control air flow through a wooden frame. The two sections of the wooden frame are joined by a paper or cardboard fan that is manually pumped to feed air through the instrument. Different notes are played by pressing keys on the side of the accordion. One side typically features circular buttons, while the other has a keyboard.

The accordion is featured prominently in Russian folk music, where the local type of accordion is known as a bayan (Russian: баян). Sometimes played solo, it is often combined with other instruments such as a balalaika.

French, German and Dutch traditional music also often features the accordion.