| Name | Meaning | Gender | Origin |
|---|
| Rebel | One that resists of defies authority | Unisex | English |
| Remmington | | Unisex | Hebrew |
| Renate | Reborn | Unisex | Latin |
| Rhino | | Unisex | Hebrew |
| Rogue | | Unisex | Hebrew |
| Rosco | Roe deer wood | Unisex | Norse |
| Roxie | Star | Unisex | Persian |
| Ryder | One who rides | Unisex | English |
| Sable | Sable (black) | Unisex | English |
| Sabre | | Unisex | Hebrew |
| Sarge | Noncommissioned Army or Air Force rank | Unisex | English |
| Sasha | Defending men | Unisex | Greek |
| Satan | The Devil and adversary of God | Unisex | English |
| Sativa | | Unisex | Hebrew |
| Sauron | | Unisex | Hebrew |
| Scar | From The Lion King | Unisex | English |
| Schnapps | Variety of strong liquor usually associated with Holland | Unisex | English |
| Scout | Observer | Unisex | American English |
| Scratch | | Unisex | Hebrew |
| Serpico | | Unisex | Hebrew |
| Shadow | Shadow | Unisex | English |
| Shady | | Unisex | Hebrew |
| Shaggy | Bushy and matted (hair), unkempt. | Unisex | English |
| Shaka | | Unisex | Hebrew |
| Shark | | Unisex | Hebrew |
| Slash | | Unisex | Hebrew |
| Smokey | A grayish blue colour. Slang for highway patrol officer | Unisex | English |
| Snake | | Unisex | Hebrew |
| Sniper | A skilled shooter who spots targets from a concealed place. | Unisex | English |
| Spartacus | From the city of Sparta | Unisex | English |