| No. | Name | Type | Language | Counties |
|---|---|---|---|---|
| 0 | Kimberly Diane O'Shaughnessy | Community | English | Crook, Deschutes, Jefferson, Klamath |
| 0 | EZELMA ANN OBUHORO | Master | English | Multnomah, Washington |
| 11 | RUTH NOEMI OCHOA | Master | English, Spanish | All |
| 0 | TRISTA MICHELLE OCHOA | Master | All | |
| 0 | WHITNEY OCONNELL | Community | English | All |
| 0 | CATHERINE ANN OEHLER | Master | English | Clackamas, Multnomah, Washington |
| 22 | 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 |