The cavaquinho (pronounced [kɐvɐˈkiɲu] in Portuguese) is a small Portuguese string instrument in the European guitar family, with four wires or gut strings.

A cavaquinho player is called a cavaquista.

A common tuning in Portugal is C G A D (non-reentrant with C being the lowest pitch, or from lower to higher pitches).

The standard tuning in Brazil is D G B D.

Other tunings include:

There are several forms of cavaquinho used in different regions and for different styles of music. Separate varieties are named for Portugal, Braga (braguinha), Minho (minhoto), Lisbon, Madeira, Brazil, and Cape Verde; other forms are the braguinha, ‘cavacolele’, cavaco, machete, and ukulele.

The machete is a variety of the cavaquinho from Madeira. It is a predecessor of the modern ukulele. The Machete de Braga (“Braga-style machete”) is called a braguinha.

The minhoto cavaquinho, associated with the Minho region in Portugal is similar to the viola braguesa. Its neck is on the same level as the body. Like the braguesa, the minhoto's sound hole was traditionally shaped like a stylized ray (fish); the shape is called “raia” in Portuguese.