The Sek (Saek) are a group of about 20,000 (1981) located on both sides of the Mekong River in northeastern Thailand and central Laos. Through extensive contact, the Sek have been largely assimilated into Lao society.
Hickey, Gerald C. (1964). "Sek." In Ethnic Groups of Mainland Southeast Asia, edited by Frank M. LeBar, Gerald C. Hickey, and John K. Musgrave, 149-150. New Haven: HRAF Press.