Surname ต้นข้าว (Tonkao 
, Tonkhao 
, ต้นข้าว) , all around the world, is a rare cognomen. The cognomen ต้นข้าว is habitual in South-eastern Asia, particularly Thailand, where it is a rare surname, and Malaysia, where it is a very rare surname. Likewise, ต้นข้าว is the forename as well as the last name.