| Name | Meaning | Gender | Origin |
|---|
| Rio | River | Male | Spanish |
| Rogue | | Unisex | Hebrew |
| Roman | Roman | Unisex | Latin |
| Romy | Sea dew | Unisex | Latin |
| Rusty | Rusty, full of rust | Unisex | American English |
| Sable | Sable (black) | Unisex | English |
| Sabre | | Unisex | Hebrew |
| Sammy | His name is God | Unisex | Hebrew |
| Sandy | Defending men | Male | Greek |
| Sasha | Defending men | Unisex | Greek |
| Sasquatch | Has extra toes and hence is a bigfoot | Unisex | English |
| Satan | The Devil and adversary of God | Unisex | English |
| Saturn | Sixth and second largest planet away from the Sun. | Unisex | English |
| Scooby | | Unisex | Hebrew |
| Sebastian | Man from Sebaste | Male | Latin |
| Shark | | Unisex | Hebrew |
| Skye | Cloud | Male | Norse |
| Smokey | A grayish blue colour. Slang for highway patrol officer | Unisex | English |
| Smoky | | Unisex | Hebrew |
| Talon | A claw | Male | English |
| Talos | Giant Protector Of Minos Island | Male | Greek |
| Tango | | Unisex | Hebrew |
| Tank | A large metal container. A heavily armed combat vehicle | Unisex | English |
| Tex | Of Texas | Unisex | English |
| Themis | Order | Unisex | Greek |
| Thunder | Stormy Tempered | Unisex | English |
| Titan | Powerful big man | Unisex | Greek |
| Trojan | | Unisex | Hebrew |
| Truman | Faithful man | Male | English |
| Ulysses | Walker | Male | Greek |