Cognomen ดุ๋ย (Dui 
, ดุ๋ย) , throughout the world, is quite a common last name. The cognomen ดุ๋ย is habitual in Taiwan, where it is quite a common surname, Malaysia, where it is quite a rare surname, and Italy, where it is a rare surname. Measured by absolute frequency, it is commonest in Taiwan, India, and China. Also, ดุ๋ย is the forename as well as the last name.