| Name | Gender | Pronounced | Usage | Popularity |
|---|---|---|---|---|
| Oswin | AHZ-win | English (Rare) | ||
| Otis | O-tis | English | ||
| Otto | AW-to (German), AH-to (English), OT-to (Finnish) | German, Swedish, Norwegian, Danish, Dutch, English, Finnish, Ancient Germanic | ||
| Ottoline | - | English (Rare) | ||
| Owen (1) | O-ən (English) | Welsh, English | ||
| Oz (1) | AHZ | English | ||
| Ozzie | AHZ-ee | English | ||
| Ozzy | AHZ-ee | English | ||
| Pace | PAYS | English (Rare) | ||
| Pacey | PAY-see | English (Rare) | ||
| Paden | PAY-dən | English (Rare) | ||
| Page | PAYJ | English | ||
| Paget | - | English (Rare) | ||
| Paige | PAYJ | English | ||
| Paisley | - | English (Modern) |