Cognomen Onsay (Onsay 
) , in the world, is a rare family name. The surname Onsay is characteristic of Philippines, where it is a rare surname, France, where it is an extremely rare surname, and Turkey. Measured by absolute frequency, it is the most numerous in Philippines, the United States, and France. Much less frequently, Onsay is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Onsay | Turkey, Cuba, France, United States, Philippines |