Circulus are a psychedelic folk/progressive rock band from South London, England, founded by vocalist Michael Tyack.

The band uses a mix of modern and medieval instruments, such as the lute, cittern, crumhorn and rauschpfeife, along with the Moog synthesizer, bass and electric guitars. Tyack claims to believe in fairies and pixies, and they have been known to play their live shows with the audience sitting on the floor.

Circulus were featured in a two-page spread of an NME issue in 2005, and a two-page interview in Terrorizer in 2006 . Their album Clocks are Like People was reviewed in Metal Hammer magazine in September 2006, receiving 8/10.

The band featured in an SVT (Swedish) music television documentary called This Is Our Music in 2005, and were interviewed on BBC2's The Culture Show on 3 February 2007 as part of an item on the 'new folk'.

Mojo magazine chose Circulus to cover "Lucy in the Sky with Diamonds" for their 40th anniversary Sgt. Pepper's Lonely Hearts Club Band tribute album, Sgt. Pepper...With a Little Help from His Friends, given away with their March 2007 issue.

In 2018 Michael Tyack confirmed a new album to be released in the summer of 2018.