| Name | Meaning | Gender | Origin |
|---|
| Sasha | Defending men | Unisex | Greek |
| Sassy | Lively and spirited | Unisex | English |
| Scooter | One who goes suddenly and speedily. | Unisex | English |
| Scout | Observer | Unisex | American English |
| Shadow | Shadow | Unisex | English |
| Shaggy | Bushy and matted (hair), unkempt. | Unisex | English |
| Shakespeare | Brandish spear | Unisex | English |
| Sheba | Daughter of an oath | Female | Hebrew |
| Shorty | Of less than average size | Unisex | English |
| Simba | Lion | Female | Swahili |
| Simon | Listening | Male | Hebrew |
| Slim | Slender in proportion to height. | Unisex | English |
| Smoky | | Unisex | Hebrew |
| Socks | Short stockings finishing above the ankle | Unisex | English |
| Soda | A carbonated water. | Unisex | English |
| Sophia | Wisdom | Female | Greek |
| Sophie | Wisdom | Female | Greek |
| Sparky | Animated, lively. | Unisex | English |
| Spike | A long, thick sharp-pointed piece of wood or metal | Male | English |
| Spot | After Data's cat on Star Trek: The Next Generation | Unisex | English |
| Spring | To burst forth | Female | English |
| Squirt | Slang for a small person | Unisex | English |
| Stumpy | A short, thickset person | Unisex | English |
| Sugar | A sweet powder from sugar cane. Slang for sweetheart. | Female | English |
| Sweetie | Sweetheart. | Unisex | English |
| Tasha | (Christ's) birthday | Female | Latin |
| Teddy | Gift of God | Male | Greek |
| Tess | Harvester | Female | Greek |
| Tia | Princess Or Crowned One | Female | English |
| Tinkerbell | | Unisex | Hebrew |