| Name | Meaning | Gender | Origin |
|---|
| Peewee | | Unisex | Hebrew |
| Pepsi | Brand of cola soft drink. | Unisex | English |
| Pinky | For Pinky Lee, the painting, and the color of her nose | Unisex | English |
| Pip | Lover of horses | Unisex | Greek |
| Pipsqueak | | Unisex | Hebrew |
| Poco | Little. | Unisex | English |
| Puddles | | Unisex | Hebrew |
| Pumpkin | Large round fruit with orange skin | Unisex | English |
| Rambo | | Unisex | Hebrew |
| Rascal | One that is playfully mischievous | Unisex | English |
| Rocio | Covered in dew | Unisex | Spanish |
| Roman | Roman | Unisex | Latin |
| Romy | Sea dew | Unisex | Latin |
| Rusty | Rusty, full of rust | Unisex | American English |
| Sammy | His name is God | Unisex | Hebrew |
| Sarge | Noncommissioned Army or Air Force rank | Unisex | English |
| Sasha | Defending men | Unisex | Greek |
| Sasquatch | Has extra toes and hence is a bigfoot | Unisex | English |
| Sassy | Lively and spirited | Unisex | English |
| Saturn | Sixth and second largest planet away from the Sun. | Unisex | English |
| Scar | From The Lion King | Unisex | English |
| Shadow | Shadow | Unisex | English |
| Shark | | Unisex | Hebrew |
| Shorty | Of less than average size | Unisex | English |
| Skittles | | Unisex | Hebrew |
| Sky | Sky | Unisex | Norse |
| Slim | Slender in proportion to height. | Unisex | English |
| Sparky | Animated, lively. | Unisex | English |
| Speedy | Rapid motion, swift. | Unisex | English |
| Squeaky | | Unisex | Hebrew |