Cognomen บุญเพ็ญ (บุญเพ็ญ 
, Boonpen 
, Bunphen 
) , throughout the world, is quite a rare last name. The last name บุญเพ็ญ is characteristic of Thailand, where it is quite a rare surname, the United Kingdom, where it is an extremely rare surname, and the United States. Likewise, บุญเพ็ญ is the forename as well as the last name.