| Name | Meaning | Gender | Origin |
|---|
| Oceana | Ocean | Female | Greek |
| Olga | Holy | Female | German |
| Olive | Olive | Female | English |
| Onyx | A gemstone with bands of different colours. | Unisex | English |
| Opal | Jewel, gem | Female | Sanskrit |
| Oreo | American cookie brand consisting of two chocolate wafers with white cream filling. | Unisex | English |
| Oriel | Bird | Female | English |
| Osiris | Uncertain, perhaps throne of the eye | Unisex | Ancient Egyptian |
| Paisley | Church, cemetery | Unisex | English |
| Pal | A friend, buddy, chum. | Unisex | English |
| Pan | Herdsman | Unisex | Greek |
| Panda | A bear like Chinese mammal, with distinct black and white markings | Unisex | English |
| Panther | A black leopard | Unisex | English |
| Pasha | Passover | Unisex | Greek |
| Pax | Peace | Unisex | Latin |
| Penny | Weaver | Female | Greek |
| Pepper | Pepper | Female | English |
| Pepsi | Brand of cola soft drink. | Unisex | English |
| Phantom | Something elusive. A ghost | Unisex | English |
| Phoebe | Bright | Female | Greek |
| Phyllis | Foliage | Female | Greek |
| Pia | Pious | Female | Latin |
| Piccolo | | Unisex | Hebrew |
| Pickles | Food flavored in a solution of vinegar | Unisex | English |
| Pig | | Unisex | Hebrew |
| Pikachu | | Unisex | Hebrew |
| Pilar | Pillar | Female | Spanish |
| Pinky | For Pinky Lee, the painting, and the color of her nose | Unisex | English |
| Pipa | | Unisex | Hebrew |
| Piper | A pipe player | Female | English |