| Name | Meaning | Gender | Origin |
|---|
| Russell | Little red one | Male | French |
| Rusty | Rusty, full of rust | Unisex | American English |
| Sam | He is called god | Male | Hebrew |
| Sammy | His name is God | Unisex | Hebrew |
| Sasha | Defending men | Unisex | Greek |
| Sassy | Lively and spirited | Unisex | English |
| Scotch | Scotch whiskey. | Unisex | English |
| Shadow | Shadow | Unisex | English |
| Shaw | Grove | Male | English |
| Shorty | Of less than average size | Unisex | English |
| Skip | Master of a Ship | Male | American English |
| Slim | Slender in proportion to height. | Unisex | English |
| Sonic | Approaching the speed of sound, fast-paced | Unisex | English |
| Sparky | Animated, lively. | Unisex | English |
| Squirt | Slang for a small person | Unisex | English |
| Stumpy | A short, thickset person | Unisex | English |
| Sweetie | Sweetheart. | Unisex | English |
| Switch | | Unisex | Hebrew |
| Tank | A large metal container. A heavily armed combat vehicle | Unisex | English |
| Taz | Wild Animal, Thrid Born | Unisex | American |
| Teddy | Gift of God | Male | Greek |
| Thane | Freeman | Male | English |
| Thunder | Stormy Tempered | Unisex | English |
| Tiger | Tiger | Unisex | English |
| Tigga | | Unisex | Hebrew |
| Tiny | Extremely small | Unisex | English |
| Toby | God is good | Unisex | Hebrew |
| Tootsie | A girl or young woman. | Unisex | English |
| Tripp | Traveler | Male | English |
| Trouble | A cause of disturbance or difficulty. | Unisex | English |