| Name | Meaning | Gender | Origin |
|---|
| Roxie | Star | Unisex | Persian |
| Rusty | Rusty, full of rust | Unisex | American English |
| Sammy | His name is God | Unisex | Hebrew |
| Sasha | Defending men | Unisex | Greek |
| Sassy | Lively and spirited | Unisex | English |
| Sausage | Chopped meat stuffed into a prepared casing and cooked. | Unisex | English |
| Scabbers | | Unisex | Hebrew |
| Schnapps | Variety of strong liquor usually associated with Holland | Unisex | English |
| Scooter | One who goes suddenly and speedily. | Unisex | English |
| Shadow | Shadow | Unisex | English |
| Shorty | Of less than average size | Unisex | English |
| Simpson | Listening | Unisex | Hebrew |
| Slim | Slender in proportion to height. | Unisex | English |
| Slinky | | Unisex | Hebrew |
| Snap | | Unisex | Hebrew |
| Snapper | | Unisex | Hebrew |
| Snickers | A brand of candy bar. | Unisex | English |
| Snuffles | | Unisex | Hebrew |
| Sparky | Animated, lively. | Unisex | English |
| Speckles | | Unisex | Hebrew |
| Spongebob | | Unisex | Hebrew |
| Squirt | Slang for a small person | Unisex | English |
| Stormy | Violent weather | Unisex | English |
| Stretch | To extend to full length. | Unisex | English |
| Stumpy | A short, thickset person | Unisex | English |
| Sunflower | | Unisex | Hebrew |
| Sunshine | Light from the sun | Unisex | English |
| Sweetie | Sweetheart. | Unisex | English |
| Toby | God is good | Unisex | Hebrew |
| Tootie | | Unisex | Hebrew |