The Banjo is a four-, five-, or six-stringed instrument with a thin membrane stretched over a frame or cavity as a resonator, called the head, which is typically circular.

Four Stringed banjos are available in two types. Firstly a plectrum banjo commonly tuned the same as the top four string of a guitar and feature a long neck. Secondly the Tenor Banjo which are commonly used in Gaelic Irish styles and rhythm play in jazz.

Five stringed banjos are commonly played with thumb and finger picks. These banjos offer a myriad of tuning options most of which are of a reentrant type. The 5 string banjo is commonly used in a picking style traditionaly heard in American old time music and jazz.

Six string banjos are a british adaptation and feature a guitar neck and tuning.

The membrane is typically made of plastic, although animal skin is still occasionally used.

Early forms of the instrument were fashioned by Africans in the United States, adapted from African instruments of similar design. The banjo is frequently associated with folk, Irish traditional, and country music.

The banjo, along with the fiddle, is a mainstay of American old-time music. It is also very frequently used in traditional ("trad") jazz.