Family name Sietu (Sietu 
) , across the world, is a very rare surname. The surname Sietu is habitual in New Zealand, where it is a very rare surname, Australia, and the United States, where it is an extremely rare surname. More frequently, Sietu is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Sietu | Algeria, Australia, United States, India, New Zealand |