| Name | Meaning | Gender | Origin |
|---|
| Rocko | | Unisex | Hebrew |
| Romy | Sea dew | Unisex | Latin |
| Rosie | Rose | Female | Latin |
| Roxie | Star | Unisex | Persian |
| Roxy | Star | Female | Persian |
| Ruby | Red | Female | Latin |
| Rusty | Rusty, full of rust | Unisex | American English |
| Sable | Sable (black) | Unisex | English |
| Sadie | Princess | Female | Hebrew |
| Saffron | From the spice or the colour, yellow | Female | English |
| Samantha | Listener | Female | Aramaic |
| Sammy | His name is God | Unisex | Hebrew |
| Sampson | Sun | Unisex | Hebrew |
| Sasha | Defending men | Unisex | Greek |
| Sassy | Lively and spirited | Unisex | English |
| Satin | Amber | Female | Armenian |
| Scooter | One who goes suddenly and speedily. | Unisex | English |
| Selena | Moon | Female | Greek |
| Shadow | Shadow | Unisex | English |
| Sheba | Daughter of an oath | Female | Hebrew |
| Shelby | A place where willows grow | Female | American English |
| Shorty | Of less than average size | Unisex | English |
| Silk | | Unisex | Hebrew |
| Simba | Lion | Female | Swahili |
| Skittles | | Unisex | Hebrew |
| Slim | Slender in proportion to height. | Unisex | English |
| Snickers | A brand of candy bar. | Unisex | English |
| Snowball | | Unisex | Hebrew |
| Snuggles | To curl up closely, cuddle | Unisex | English |
| Socks | Short stockings finishing above the ankle | Unisex | English |