Ko Tao (also often Koh Tao, Thai: เกาะเต่า, Thai pronunciation: [kɔ̀ʔ tàw], lit. "Turtle Island") is an island in Thailand and forms part of the Chumphon Archipelago on the western shore of the Gulf of Thailand. It covers an area of about 21 km². Administratively it forms a tambon within the district (amphoe) Ko Pha Ngan of Surat Thani Province.