Flyer called a circular, handbill or leaflet is a single-page leaflet advertising. Flyers are typically used by individuals or businesses to promote their products or services. They are a form of mass marketing or small scale, community communication. The verb "flyering" or "fliering" has evolved as a colloquial expression meaning "to put up flyers".

Flyers, along with postcards, pamphlets and small posters, are forms of communication for people who want to engage the public but do not have the money or desire to advertise over the internet, in telephone directories, or classified or display advertising in newspapers or other periodicals. As marketing became more direct in the late 1980s and 1990s, flyers evolved[citation needed] and currently there are many formats to be found.