| Name | Meaning | Gender | Origin |
|---|
| 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 |
| Spot | after Data's cat on Star Trek: The Next Generation | Male | |
| Spotty | Marked with spots | Unisex | |
| Sprinkles | | Unisex | |
| Spumoni | | Unisex | |
| Stella | a star | Female | Latin |
| Stella | a star | Female | Latin |
| Stormy | | Female | |
| Streak | | Unisex | |
| Stripe | | Unisex | |
| Stripey | | Unisex | Hebrew |
| Sugar | A sweet powder from sugar cane. Slang for sweetheart. | Female | Literary |
| Sugar | A sweet powder from sugar cane. Slang for sweetheart. | Female | Literary |
| Sydney | from city of St. Denis | Female | |
| Tabby | | Unisex | |
| Tabetha | | Unisex | |
| Tabitha | gazelle, roe-buck | Female | Aramaic |
| Tank | A large metal container. A heavily armed combat vehicle | Unisex | |
| Tawny | A light brown colour | Female | English |
| Taz | | Male | |
| Teagan | beautiful | Female | Irish |
| Terra | earth | Female | Latin |
| Theo | divine gift | Male | English |
| Thor | Viking mythology: the ruler of the weather | Male | Norse |