Dōjinshi (同人誌^?, often transliterated as doujinshi) is the Japanese term for self-published works, usually magazines, manga or novels. Dōjinshi are often the work of amateurs, though some professional artists participate as a way to publish material outside the regular industry. The term dōjinshi is derived from dōjin (同人^?, literally "same person", used to refer to a person or persons with whom one shares a common goal or interest) and shi (誌^?, a suffix generally meaning "periodical publication"). Dōjinshi are part of a wider category of dōjin including, but not limited to, art collections, anime, hentai and games. Groups of dōjinshi artists refer to themselves as a sākuru (サークル^?, circle). A number of such groups actually consist of a single artist: they are sometimes called kojin sākuru (個人サークル^?, personal circles).

Dōjinshi are made by artists or writers who prefer to publish their own materials. Since the 1980s, the main method of distribution has been through regular dōjinshi conventions, the largest of which is called Comiket (short for "Comic Market") held in the summer and winter in Tokyo's Big Sight. At the Convention, over 20 acres (81,000 m²) of dōjinshi are bought, sold, and traded by attendees. Dōjinshi creators who based their materials on other creators' works normally publish in small numbers to maintain a low profile from litigation. This makes a talented creator's or circle's dōjinshi a coveted commodity as only the fast or the lucky will be able to get them before they sell out.