Freak Folk is a style that uses mainly acoustic instruments; mostly guitar (often in alternate tunings) and occasionally violin or flute, accompanied by percussion instruments such as bongos. Used correctly, it tends to refer to music with long instrumental/psychedelic passages (and that may utilize drones), or "poppier" folk music with elaborately baroque, psychedelic or oppressive atmospheres. Some modern singer-songwriters are tagged as Freak Folk just for looking a bit peculiar.

It is a term associated with contemporary artists like Joanna Newsom, Cocorosie, Six Organs of Admittance, Akron/Family, Rio en Medio, Charalambides, and with '60s Acid Folk artists like the Holy Modal Rounders, The Incredible String Band, Tyrannosaurus Rex, The Godz and The Fugs.