iiyama is a brand name of Mouse Computer Corporation (株式会社マウスコンピューター, Kabushiki Gaisha Mausu Konpyūtā).

It was previously an independent Japanese computer electronics company called Iiyama Corporation (株式会社イーヤマ, Kabushikigaisha Īyama) with its headquarters in Chiyoda-ku, Tokyo.

The company was bought in January 2006 by MCJ, which includes Mouse Computer Corporation.

Founded in March 1972 as Iiyama Electric Corporation (飯山電機株式会社) by 23-year-old bank employee Kazuro Katsuyama, it first started manufacturing television boards and substrates for Mitsubishi at a local plant in Nagano Prefecture.

The company expanded to the Western market in 1987 and in the 1990s opened up offices in Philadelphia, Germany, Poland, France, UK, Sweden, the Czech Republic, Taiwan, and its international head office in the Netherlands, where it is registered as Iiyama Benelux B.V. By 1993 it was the leading monitor supplier in Japan with a 21% market share.