Last name Tachai (Ташай 
, Tachai 
, ทาชัย ) , around the world, is a rare family name. The cognomen Tachai is characteristic of Thailand, where it is a rare surname, Kyrgyzstan, where it is a very rare surname, and Kazakhstan. In absolute terms, it is commonest in Thailand, Nigeria, and Kazakhstan. Also, Tachai is the forename as well as the last name.