| Name | Meaning | Gender | Origin |
|---|
| Simba | lion | Male | Swahili |
| Simon | he who hears | Male | Hebrew |
| Skittles | | Male | |
| Skittles | | Male | |
| Smokey | A grayish blue colour. Slang for highway patrol officer | Male | |
| Smokey | A grayish blue colour. Slang for highway patrol officer | Male | |
| Smokey | A grayish blue colour. Slang for highway patrol officer | Male | |
| Smokie | | Unisex | Hebrew |
| Smudge | A blotch or smear | Male | |
| Snickers | A brand of candy bar. | Unisex | |
| Snickers | A brand of candy bar. | Unisex | |
| Snoopy | | Male | |
| Snowball | | Unisex | |
| Snowflake | Single flake or crystal of snow. | Unisex | |
| Snowy | Covered with snow | Unisex | |
| Snuggles | To curl up closely, cuddle | Male | |
| Snuggles | To curl up closely, cuddle | Male | |
| Socks | Short stockings finishing above the ankle | Unisex | |
| Sonny | A boy or young man. | Male | Nickname |
| Sox | Short stockings finishing above the ankle | Unisex | |
| Sox | Short stockings finishing above the ankle | Unisex | |
| Spanky | | Unisex | |
| Sparky | Animated, lively. | Unisex | |
| Sparta | | Unisex | |
| Spaz | For a spazy kitty
| Male | |