| Name | Meaning | Gender | Origin |
|---|
| Oscar | Divine spear | Male | English |
| Pax | Peace | Unisex | Latin |
| Pluto | Wealth, riches | Unisex | Greek |
| Pollux | Coronet | Unisex | Greek |
| Rainbow | Rainbow | Unisex | English |
| Rambo | | Unisex | Hebrew |
| Ranger | Gamekeeper | Male | English |
| Rebel | One that resists of defies authority | Unisex | English |
| Riley | Rye clearing | Male | English |
| River | River | Unisex | English |
| Rocky | Battle cry | Male | Germanic |
| Rogue | | Unisex | Hebrew |
| Roman | Roman | Unisex | Latin |
| Rudy | Famous wolf | Male | Germanic |
| Rufus | Red | Male | Latin |
| Rusty | Rusty, full of rust | Unisex | American English |
| Saber | Patient | Male | English |
| Sable | Sable (black) | Unisex | English |
| Sabre | | Unisex | Hebrew |
| Sam | He is called god | Male | Hebrew |
| Sammy | His name is God | Unisex | Hebrew |
| Sampson | Sun | Unisex | Hebrew |
| Samson | Sun | Male | Hebrew |
| Sandy | Defending men | Male | Greek |
| 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 |
| Scooter | One who goes suddenly and speedily. | Unisex | English |