| Name | Meaning | Gender | Origin |
|---|
| Smoke | | Unisex | |
| 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 | |
| Smoky | | Unisex | |
| Sneezy | | Unisex | Hebrew |
| Snoop | To pry into the private affairs of others | Unisex | |
| Snorky | | Unisex | Hebrew |
| Snowball | | Unisex | |
| Snowflake | Single flake or crystal of snow. | Unisex | |
| Sobek | | Unisex | |
| Sooty | Covered with soot | Unisex | |
| Sorrel | reddish brown | Male | Botanical |
| Space | | Unisex | |
| Sparky | Animated, lively. | Unisex | |
| Spencer | Shopkeeper, dispenser, keeper | Male | English |
| Spook | | Unisex | |
| Spot | after Data's cat on Star Trek: The Next Generation | Male | |
| Squeaky | | Unisex | |
| Squirt | Slang for a small person | Unisex | |
| Storm | Storm
| Male | Word |
| Styx | from Greek mythology, the river that formed the boundary between earth and the underworld | Unisex | |
| Sultan | A ruler of a Moslem country | Male | Swahili |
| Sunflower | | Unisex | |
| Sunny | Abounding in sunshine, cheerful | Male | Nickname |