MOS Food Services, Inc. (株式会社モスフードサービス), doing business as MOS Burger (モスバーガー) (which stands for "Mountain Ocean Sun"[4]), is a multinational fast-food restaurant chain (fast-casual) from Japan. Its headquarters are in the ThinkPark Tower in Ōsaki, Shinagawa, Tokyo.[2] At one time its headquarters were located in Shinjuku, Tokyo.[5][6] Japan's answer to McDonald's, it is the second-largest fast-food franchise in Japan (after McDonald's). It owns numerous overseas outlets over East Asia, Southeast Asia and Oceania, including China, Taiwan, Hong Kong, South Korea, Singapore, Thailand, Indonesia and the Philippines. "MOS Burger" is also the name of the standard hamburger offered by the restaurant, having been its first product when it opened in 1972.
MOS Burger's outlets are located in suburban areas to avoid the rising land costs in central areas where the outlets of its competitor McDonald's are located.