Stringed instruments are musical instruments that produce sound from vibrating strings when the performer plays or sounds the strings in some manner.

Musicians play some string instruments by plucking the strings with their fingers or a plectrum—and others by hitting the strings with a light wooden hammer or by rubbing the strings with a bow. In some keyboard instruments, such as the harpsichord or piano, the musician presses a key that plucks the string or strikes it with a hammer.

With bowed instruments, the player rubs the strings with a horsehair bow, causing them to vibrate. With a hurdy-gurdy, the musician operates a mechanical wheel that rubs the strings.

In most string instruments, the vibrations are transmitted to the body of the instrument, which often incorporates some sort of hollow or enclosed area. The body of the instrument also vibrates, along with the air inside it. The vibration of the body of the instrument and the enclosed hollow or chamber make the vibration of the string more audible to the performer and audience. The body of most string instruments is hollow. Some, however—such as electric guitar and other instruments that rely on electronic amplification—may have a solid wood body.