Worldwide, Oncea (Oncea 
) is a very rare predominantly male, but very infrequently female first name. The first name Oncea is habitual in Eastern Europe, particularly Romania, where it is a rare boy's name. More frequently, Oncea is the last name as well as the forename.
| VARIANT | COUNTRY |
|---|---|
| Oncea | Canada, Moldova, Poland, United States, Romania |
Sam, Ioana, Marius, Samuel, Stefan, Adrian, Cheryl, Rodica, Denisa, Daniel, George, Laurie, Lenuta, Joanne, Jennie, Judith, Vasile, Victor, Ileana, Ivonka, Ofelia, Wiorel, Ionut, Melanie, Elena, Jayne, Ana, Ian, Sean, Alex, Alin, Cami, Jack, John, Ivan, Igor, Ioan, Maria, Mihai, Sanda, Scott, Brian, Patti, David, Laura, Lynne, James, Jerry, and Michael