| Name | Meaning | Gender | Origin |
|---|
| Spam | | Unisex | Hebrew |
| Spanky | | Unisex | |
| Sparkle | To shine with animation | Unisex | |
| Sparky | Animated, lively. | Unisex | |
| Spaz | For a spazy kitty
| Male | |
| Speedy | Rapid motion, swift. | Unisex | |
| Spider | An eight legged insect | Unisex | |
| Spike | A long, thick sharp-pointed piece of wood or metal | Male | American |
| Spirit | Part of the human being associated with the mind. Vigorous or animated state - spirited. Also distilled alcohol. | Female | Word |
| Spook | | Unisex | |
| Spot | after Data's cat on Star Trek: The Next Generation | Male | |
| Spud | Slang for potato. | Male | |
| Squeak | | Unisex | |
| Squib | | Unisex | Hebrew |
| Stanley | Lives by the stony grove
| Male | English |
| Star | A celestial body that emits light. A famous performer. | Female | Word |
| Star | A celestial body that emits light. A famous performer. | Female | Word |
| Starfire | | Unisex | |
| Steele | | Unisex | |
| Stella | a star | Female | Latin |
| Stella | a star | Female | Latin |
| Sterling | British money or coin. A type of silver. Of good character. genuine, valued | Male | English |
| Stetson | Cowboy Hat | Male | English |
| Stoner | | Unisex | |
| Storm | Storm
| Male | Word |