| Name | Meaning | Gender | Origin |
|---|
| Quinn | Descendent of Cuinn | Male | Gaelic |
| Rad | Thunder | Male | Arabic |
| Rambo | | Unisex | Hebrew |
| Rascal | One that is playfully mischievous | Unisex | English |
| Rex | King | Male | Latin |
| Rick | Strong power | Male | French |
| Robby | Bright fame | Unisex | Germanic |
| Rocco | Battle cry | Male | Germanic |
| Rocko | | Unisex | Hebrew |
| Rocky | Battle cry | Male | Germanic |
| Rodney | Renown island | Male | English |
| Rufus | Red | Male | Latin |
| Saber | Patient | Male | English |
| Sable | Sable (black) | Unisex | English |
| Samson | Sun | Male | Hebrew |
| Sandy | Defending men | Male | Greek |
| Sarge | Noncommissioned Army or Air Force rank | Unisex | English |
| Sasha | Defending men | Unisex | Greek |
| Saturn | Sixth and second largest planet away from the Sun. | Unisex | English |
| Scar | From The Lion King | Unisex | English |
| Skeet | Swift | Male | English |
| Snowflake | Single flake or crystal of snow. | Unisex | English |
| Snuggles | To curl up closely, cuddle | Unisex | English |
| Soda | A carbonated water. | Unisex | English |
| Spade | | Unisex | Hebrew |
| Sparky | Animated, lively. | Unisex | English |
| Spartacus | From the city of Sparta | Unisex | English |
| Spike | A long, thick sharp-pointed piece of wood or metal | Male | English |
| Sunshine | Light from the sun | Unisex | English |
| Talon | A claw | Male | English |