Cognomen סידני (Sidney 
, Sydney , Sidni 
) , worldwide, is a common surname. The surname סידני is habitual in Saint Lucia, where it is quite a common surname, Jersey, and Cabo Verde (explore the name in all countries). Not in comparison with a country's population, this name is the most popular in the United States, Nigeria, and Australia. More frequently, סידני is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Sydney, Sidney | South Africa, Zambia, United States, Brazil, Democratic Republic of the Congo |
| Sidni | Philippines, Nigeria, United States, Canada, Brazil |
| סידני | Israel |