Last name เพ็ญสุข (Happiness 
, เพ็ญสุข 
, Pensuk 
) , in all the world, is a common surname. The cognomen เพ็ญสุข is habitual in Nigeria, where it is quite a common surname, Thailand, where it is quite a rare surname, and Niger, where it is a rare surname. In absolute terms, it is the most numerous in Nigeria, Thailand, and South Africa. Likewise, เพ็ญสุข is the forename as well as the last name.