| Name | Meaning | Gender | Origin |
|---|
| Snoopy | | Unisex | Hebrew |
| Snowflake | Single flake or crystal of snow. | Unisex | English |
| Snuffles | | Unisex | Hebrew |
| Snuggles | To curl up closely, cuddle | Unisex | English |
| Socks | Short stockings finishing above the ankle | Unisex | English |
| Socrates | Uncertain meaning | Male | Greek |
| Solo | | Unisex | Hebrew |
| Solomon | Peace | Male | Hebrew |
| Spam | | Unisex | Hebrew |
| Spanky | | Unisex | Hebrew |
| Sparkey | | Unisex | Hebrew |
| Sparkle | To shine with animation | Unisex | English |
| Speedy | Rapid motion, swift. | Unisex | English |
| Sphinx | | Unisex | Hebrew |
| Spider | An eight legged insect | Unisex | English |
| Spike | A long, thick sharp-pointed piece of wood or metal | Male | English |
| Spinner | | Unisex | Hebrew |
| Spirit | Part of the human being associated with the mind. Vigorous or animated state - spirited. Also distilled alcohol. | Unisex | English |
| Splash | To cause fluid to scatter in flying masses. To display very noticeably. | Unisex | English |
| Spooky | | Unisex | Hebrew |
| Spot | After Data's cat on Star Trek: The Next Generation | Unisex | English |
| Sprite | Lemonade flavored soft drink. | Unisex | English |
| Spunky | Spirited, plucky. | Unisex | English |
| Sputnik | | Unisex | Hebrew |
| Squeaky | | Unisex | Hebrew |
| Squirt | Slang for a small person | Unisex | English |
| Stanley | Meadow that is stony | Male | English |
| Stardust | | Unisex | Hebrew |
| Starlight | | Unisex | Hebrew |
| Sterling | Little star - stellar | Male | English |