| Name | Meaning | Gender | Origin |
|---|
| Rambo | | Unisex | Hebrew |
| Rebel | One that resists of defies authority | Unisex | English |
| River | River | Unisex | English |
| Rogue | | Unisex | Hebrew |
| Roman | Roman | Unisex | Latin |
| Rosie | Rose | Female | Latin |
| Roxy | Star | Female | Persian |
| Ruby | Red | Female | Latin |
| Rusty | Rusty, full of rust | Unisex | American English |
| Sable | Sable (black) | Unisex | English |
| Sabre | | Unisex | Hebrew |
| Sadie | Princess | Female | Hebrew |
| Sammy | His name is God | Unisex | Hebrew |
| Sampson | Sun | 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 |
| Scooter | One who goes suddenly and speedily. | Unisex | English |
| Scout | Observer | Unisex | American English |
| Serena | Composed | Female | Latin |
| Shadow | Shadow | Unisex | English |
| Shaggy | Bushy and matted (hair), unkempt. | Unisex | English |
| Shark | | Unisex | Hebrew |
| Shasta | Name of a Native American tribe | Female | Native American |
| Sheba | Daughter of an oath | Female | Hebrew |
| Shiloh | Gift for him | Unisex | Hebrew |
| Sierra | Mountain range | Female | Spanish |
| Simba | Lion | Female | Swahili |