Family name กตัญญู (กตัญญู 
, Katanyu 
, Katanyoo 
, and others...) , across the world, is quite a rare last name. The cognomen กตัญญู is habitual in Thailand, where it is quite a rare surname, and New Zealand, where it is a very rare surname. Likewise, กตัญญู is the forename as well as the last name.