COMITIA (Japanese: コミティア, Hepburn: Komitia) is a doujinshi convention for original doujin (self-published) works held in various locations across Japan. COMITIA is typically held four times per year in Tokyo, and 2–3 times per year in Niigata (since 1991), Nagoya (since January 1993), and the Kansai region (since April 1993). Less regular events are also hosted in Sapporo (since 2014), Tōhoku (since 2015), and Kitakyushu (since 2017).^[2] As an event series focusing on non-derivative work, the sale of fan art, fanzines, fan fiction, and other parody material of existing copyrighted franchises is prohibited. It is the largest convention focused completely on original works in Japan.^[1]

Various high-profile manga artists, such as Keiichi Arawi and Kenshin Shinzato [ja], have previously exhibited at COMITIA.^[3][4][5]

Since 1984, COMITIA has been hosted regularly by the COMITIA Organizational Committee, a not-for-profit volunteer organization.^[6] Events in Tokyo are referred to as Tokyo COMITIA while other cities feature conventions known as Regional COMITIA (地方コミティア, Chihō Komitia), which are organized by other volunteer-run groups.^[2] The Niigata event shares an organizational team with Niigata Comic Market.

The COVID-19 pandemic resulted in the cancellation of multiple COMITIA events. A crowdfunding campaign was held in late 2020 and resulted in over ¥100 million (US$960,000) being raised to cover administrative expenses, venue fees, and the purchase of personal protective equipment for use during future events.^[7][8]