Surname Портнои (Portnoy 
, Портнои 
) , around the world, is quite a rare last name. The cognomen Портнои is habitual in Israel, where it is quite a common surname, Argentina, where it is a rare surname, and the United States. Not in comparison with a country's population, it is commonest in the United States, Israel, and Indonesia.
| VARIANT | COUNTRY |
|---|---|
| Portnoy | Colombia, Argentina, United States, Israel, Indonesia |
| Портнои | Russia |