| No. | Name | Type | Language | Counties |
|---|---|---|---|---|
| 23 | Soobin David Oh | Master | English | All |
| 117 | HEATHER OLEARY | Master | English | All |
| 1 | Katherine Elaine Olinger | Master | English | All |
| 0 | Yamel Olivas Solis | Standardized | Spanish | Clackamas, Multnomah, Washington, Yamhill |
| 0 | Laura Ann Olson | Master | English | Clackamas, Marion, Multnomah, Polk, Yamhill |
| 23 | Kim (Kiki) Omoto | Master | English | Benton |
| 1 | LISSET ONEILL | Master | English, Spanish | Multnomah |
| 1 | Nancy L Orem | Master | English | All |
| 1 | RAUL DAVID OROZCO FUENTES | Master | English, Spanish | Benton, Linn, Marion, Polk |
| 0 | Kay Guadalupe Ortega | Standardized | English, Spanish | Jackson, Jefferson, Josephine, Klamath |