| Name | Meaning | Gender | Origin |
|---|
| Rocky | Battle cry | Male | Germanic |
| Romeo | Pilgrim to Rome | Male | Italian |
| Romy | Sea dew | Unisex | Latin |
| Rowan | Little red one | Male | Gaelic |
| Rudy | Famous wolf | Male | Germanic |
| Rufus | Red | Male | Latin |
| Rusty | Rusty, full of rust | Unisex | American English |
| Sacha | Protector of man | Male | Greek |
| 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 |
| Santos | Saints | Male | Spanish |
| Sasha | Defending men | Unisex | Greek |
| Sassy | Lively and spirited | Unisex | English |
| Scout | Observer | Unisex | American English |
| Sebastian | Man from Sebaste | Male | Latin |
| Shadow | Shadow | Unisex | English |
| Shamrock | | Unisex | Hebrew |
| Shorty | Of less than average size | Unisex | English |
| Slim | Slender in proportion to height. | Unisex | English |
| Smokey | A grayish blue colour. Slang for highway patrol officer | Unisex | English |
| Smoky | | Unisex | Hebrew |
| Sparkle | To shine with animation | Unisex | English |
| Sparky | Animated, lively. | Unisex | English |
| Spice | Plant used to flavour food or beverages. | Unisex | English |
| Spike | A long, thick sharp-pointed piece of wood or metal | Male | English |
| Spirit | Part of the human being associated with the mind. Vigorous or animated state - spirited. Also distilled alcohol. | Unisex | English |
| Spot | After Data's cat on Star Trek: The Next Generation | Unisex | English |