Cognomen Koykul (Koykul 
) , around the globe, is a rare family name. The surname Koykul is habitual in South-eastern Asia, particularly Thailand, where it is a rare surname.
Pisal, Woottikorn, Weerachai, Nutthakit, Chitraporn, Supawadee, Sasiprapa, Nuttawat, Nutthawasu, Busakorn, Usanisa, Thisinee, Rujirat, Paothep, Parita, Chalit, Arunya, Sasinisita, and Chalermpong