Any musical instrument played using a keyboard. The most common of these is the piano, which is used in nearly all forms of Western music. Other widely used keyboard instruments include various types of organs as well as other mechanical, electromechanical and electronic instruments.

In common language, the term is mostly used to refer to keyboard-style synthesizers.

Clavier is a general term for any keyboard instrument and was used especially in the 18th century and earlier in Germany to refer indiscriminately to the harpsichord, clavichord and pipe organ.

Keyboard instruments broadly divide into:

• chordophones - which make their sound when a stretched string vibrates (e.g. piano and harpsichord, which are sometimes classified as stringed instruments)
• aerophones - which produce sound primarily by causing a body of air to vibrate, without the use of strings or membranes, and without the vibration of the instrument (e.g. accordion, harmonium, organ)