| Name | Meaning | Gender | Origin |
|---|
| Rocket | To move swiftly and powerfully | Unisex | English |
| Rocky | Battle cry | Male | Germanic |
| Rogue | | Unisex | Hebrew |
| Rolo | Burmese | Unisex | English |
| Romeo | Pilgrim to Rome | Male | Italian |
| Rudy | Famous wolf | Male | Germanic |
| Rufus | Red | Male | Latin |
| Rusty | Rusty, full of rust | Unisex | American English |
| Sabre | | Unisex | Hebrew |
| Sage | Aromatic herb | Unisex | English |
| Sam | He is called god | Male | Hebrew |
| Sammy | His name is God | Unisex | Hebrew |
| Samson | Sun | Male | Hebrew |
| Sandy | Defending men | Male | Greek |
| Santo | Sacred | Male | Italian |
| Sasha | Defending men | Unisex | Greek |
| Sassy | Lively and spirited | Unisex | English |
| Scout | Observer | Unisex | American English |
| Sebastian | Man from Sebaste | Male | Latin |
| Sergio | Servant | Male | Latin |
| Seth | Appointed | Male | Hebrew |
| Shadow | Shadow | Unisex | English |
| Shorty | Of less than average size | Unisex | English |
| Silver | Silver (the metal or colour) | Male | English |
| Silvio | Wooded | Male | Latin |
| Skittles | | Unisex | Hebrew |
| Slim | Slender in proportion to height. | Unisex | English |
| Smoky | | Unisex | Hebrew |
| Solo | | Unisex | Hebrew |
| Sonic | Approaching the speed of sound, fast-paced | Unisex | English |