Freak folk is a type of Psychedelic Folk which emerged in the late 1990s and early 2000s among artists associated with the New Weird America movement. It draws from a wide range of influences, with a particular interest in 1960s hippie acid folk, other New Weird America bands, as well as elements of traditional folk music. Freak folk tends to favour finger-picked instruments like acoustic guitar, ukulele or harp, as well as toy instruments, but it can also add electric or electronic instrumentation more typical of Rock music. Peculiar, vivid and idiosyncratic vocal styles are common, ranging from the plaintive, childlike singing of Joanna Newsom to the lonesome warble of Devendra Banhart and high harmonies of Animal Collective. Production-wise, freak folk songs can frequently be very lo-fi, but some artists opt for a lush and polished approach. Lyrically, the genre usually evokes mythical, pastoral and romantic themes.

The roots of freak folk can be traced back to the 1960s, especially to the music of Vashti Bunyan who has been dubbed the "godmother of freak folk". Other influences include Nick Drake, Linda Perhacs, The Incredible String Band, Tyrannosaurus Rex, the finger-picking techniques of John Fahey and Bert Jansch, the lyrical style of Donovan and Marc Bolan, the vocals of Karen Dalton, as well as non-Western artists such as Ali Akbar Khan and Ali Farka Touré. These stylings have been revived in the 1990s by Six Organs of Admittance and other bands within New Weird America before the genre broke through to the mainstream in 2004 with albums such as Rejoicing in the Hands, Sung Tongs, The Milk-Eyed Mender, as well as The Golden Apples of the Sun, a various artists compilation curated by Devendra Banhart. The American freak folk scene had their counterparts in the New Weird Finland movement, with artists such as Islaja and Lau Nau creating a more Free Folk and Avant-Folk influenced style.

The term "freak folk" was popularized by journalists in the early 2000s, though it was often considered derogatory by associated artists who would mostly reject it. Many of them have abandoned the style after the early phase of their careers, but some like CocoRosie have continued to release freak folk albums throughout the 2010s.