The cavaquinho (pronounced [kavɐˈkiɲu] in Portuguese) is a small string instrument of the European guitar family with four wire or gut strings. It is also called machimbo, machim, machete (in the Portuguese Atlantic islands), manchete or marchete, braguinha or braguinho, or cavaco.

The most common tuning is D-G-B-D (from lower to higher pitches); other tunings include D-A-B-E (Portuguese ancient tuning, made popular by Júlio Pereira) and G-G-B-D and A-A-C#-E. Guitarists often use D-G-B-E tuning to emulate the highest four strings of the guitar. The G-C-E-A tuning is sometimes used to emulate the soprano/tenor ukulele, an instrument developed from the cavaquinhos brought to Hawai'i by Portuguese immigrants in the late 19th century. A cavaquinho player is called a cavaquista.