One of the hybrids that resulted.from the heyday of mandolin orchestras and banjo bands (late 19th–early 20th century), the mandolin-banjo adds the banjo's volume to the mandolin. It combines a banjo body with the neck and tuning of a mandolin or violin (depending on whether fretted or not and how many strings it has). It has the same scale length as a mandolin (about 14 inches), with 4 courses of strings tuned identically to the violin and mandolin (low to high GDAE). The moveable bridge stands on a resonant banjo-like head typically 10 inches in diameter and currently usually made of plastic. Originally heads were made of skin and varied in diameter to as small as 5 inches. Larger heads were favoured, however, as they were louder, and thus more audible in band settings.

The instrument has been independently invented in more than one country, being called banjolin and banjourine in English speaking countries, banjoline and bandoline in France and the cümbüş in Turkey. The name banjolin is said to be confined to a 4-string form, but in fact was first patented in 1885 for an instrument with 4 pairs of strings and is now commonly used interchangeably with mandolin-banjo.