| Name | Meaning | Gender | Origin |
|---|
| Rusty | Covered in rust - a brownish red colour. | Unisex | |
| Sam | to hear | Male | English |
| Sammy | Hebrew, told by God | Male | English |
| Samson | Bright sun
| Male | Hebrew |
| Sandy | Abbreviation of Alexander defender of man.
| Male | Scottish |
| Sarge | Noncommissioned Army or Air Force rank | Male | |
| Scooby | | Unisex | |
| Scooter | One who goes suddenly and speedily. | Male | |
| Scout | One dispatched from main body to gather information | Male | Word |
| Scrappy | Quarrelsome. Full of fighting spirit | Male | |
| Sexy | | Unisex | |
| Shamus | Supplanter | Male | Anglicized |
| Simba | lion | Male | Swahili |
| Simba | from The Lion King | Male | Swahili |
| Skittles | | Male | |
| Skittles | | Male | |
| Snickers | A brand of candy bar. | Unisex | |
| Snickers | A brand of candy bar. | Unisex | |
| Snoopy | | Male | |
| Snowball | | Unisex | |
| Sparkey | | Male | Hebrew |
| Sparky | Animated, lively. | Unisex | |
| Spencer | Shopkeeper, dispenser, keeper | Male | English |
| Spike | A long, thick sharp-pointed piece of wood or metal | Male | American |
| Taco | A folded fried tortilla filled with meat, cheese and spices. | Unisex | |