| Name | Meaning | Gender | Origin |
|---|
| Sienna | Reddish orange-brown | Female | Italian |
| Sierra | Mountain range | Female | Spanish |
| Sigma | | Unisex | Hebrew |
| Silvia | Wooded | Female | Latin |
| Simba | Lion | Female | Swahili |
| Simone | Listening | Female | Hebrew |
| Skittles | | Unisex | Hebrew |
| Sky | Sky | Unisex | Norse |
| Slim | Slender in proportion to height. | Unisex | English |
| Smokie | | Unisex | Hebrew |
| Smoky | | Unisex | Hebrew |
| Snowball | | Unisex | Hebrew |
| Snowflake | Single flake or crystal of snow. | Unisex | English |
| Socks | Short stockings finishing above the ankle | Unisex | English |
| Sonic | Approaching the speed of sound, fast-paced | Unisex | English |
| Sophia | Wisdom | Female | Greek |
| Sophie | Wisdom | Female | Greek |
| Sparkle | To shine with animation | Unisex | English |
| Sparky | Animated, lively. | Unisex | English |
| Spartacus | From the city of Sparta | Unisex | English |
| Sphinx | | Unisex | Hebrew |
| Spice | Plant used to flavour food or beverages. | Unisex | 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 |
| Spud | Slang for potato. | Unisex | English |
| Squeaky | | Unisex | Hebrew |
| Squirt | Slang for a small person | Unisex | English |
| Star | Star | Female | Latin |
| Stardust | | Unisex | Hebrew |