Family name Vilaisak (Vilaisak 
) , all around the world, is a rare cognomen. The cognomen Vilaisak is habitual in Laos, where it is quite a rare surname, Thailand, where it is a very rare surname, and the United Kingdom, where it is an extremely rare surname. Not in comparison with a country's population, it is the most numerous in Laos, Thailand, and the United States. More frequently, Vilaisak is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Vilaisak | Thailand, France, Laos, United States, United Kingdom |