Cognomen อรรถจันทร์ (Atthachan 
, อรรถจันทร์ , Atthajan) , around the world, is a very rare surname. The last name อรรถจันทร์ is habitual in South-eastern Asia, particularly Thailand, where it is a very rare surname. Much less frequently, อรรถจันทร์ is the forename as well as the last name.