| Name | Type | Language | Counties |
|---|---|---|---|
| Frank Thomas O'Hearn | Standardized | All | |
| ERIN JEAN O'REGAN | Master | English | Multnomah |
| Amie O'Rourke | Master | English | Benton, Linn |
| Kimberly Diane O'Shaughnessy | Community | English | Crook, Deschutes, Jefferson, Klamath |
| HENRY OBELNICKI | Master | English | Clatsop, Columbia, Hood River, Lincoln, Multnomah, Washington |
| EZELMA ANN OBUHORO | Master | English | Multnomah, Washington |
| RUTH NOEMI OCHOA | Master | English, Spanish | All |
| TRISTA MICHELLE OCHOA | Master | All | |
| WHITNEY OCONNELL | Community | English | All |
| CATHERINE ANN OEHLER | Master | English | Clackamas, Multnomah, Washington |