| Name | Meaning | Gender | Origin |
|---|
| Snugglepuss | | Unisex | Hebrew |
| Snuggles | To curl up closely, cuddle | Male | |
| Snuggles | To curl up closely, cuddle | Male | |
| Socks | Short stockings finishing above the ankle | Unisex | |
| Socrates | | Male | |
| Sooty | Covered with soot | Unisex | |
| Spanky | | Unisex | |
| Spartacus | from the city of Sparta | Male | Latin |
| Spaz | For a spazy kitty
| Male | |
| Spencer | Shopkeeper, dispenser, keeper | Male | English |
| Spider | An eight legged insect | Unisex | |
| Spike | A long, thick sharp-pointed piece of wood or metal | Male | American |
| Spooky | | Unisex | |
| Spot | after Data's cat on Star Trek: The Next Generation | Male | |
| Starlight | | Unisex | |
| Stash | | Unisex | |
| Steamer | | Unisex | Hebrew |
| Steel | Strong metal alloy made of iron and carbon. Hard unflinching character. | Male | Word |
| Sterling | British money or coin. A type of silver. Of good character. genuine, valued | Male | English |
| Steve | garland, crown | Male | English |
| Storm | Storm
| Male | Word |
| Strider | | Unisex | Hebrew |
| Stripes | | Unisex | |
| Stripey | | Unisex | Hebrew |
| Stubby | | Unisex | |