| Name | Meaning | Gender | Origin |
|---|
| Reese | Enthusiasm | Male | Welsh |
| Rex | King | Male | Latin |
| Riley | Rye clearing | Male | English |
| Ringo | Apple, peace be with you | Male | English |
| Rocco | Battle cry | Male | Germanic |
| Rolf | Famous wolf | Male | Germanic |
| Romeo | Pilgrim to Rome | Male | Italian |
| Rowdy | Boisterous. Western Nickname. | Unisex | English |
| Rudy | Famous wolf | Male | Germanic |
| Rupert | Bright fame | Male | English |
| Rusty | Rusty, full of rust | Unisex | American English |
| Sassy | Lively and spirited | Unisex | English |
| Sawyer | One who saws wood | Male | English |
| Scooby | | Unisex | Hebrew |
| Scooter | One who goes suddenly and speedily. | Unisex | English |
| Scout | Observer | Unisex | American English |
| Shamus | Supplanter | Male | Hebrew |
| Smoky | | Unisex | Hebrew |
| Spartacus | From the city of Sparta | Unisex | English |
| Spencer | Someone who gives out goods | Male | French |
| Spike | A long, thick sharp-pointed piece of wood or metal | Male | English |
| Suzie | Lily | Unisex | Hebrew |
| Tango | | Unisex | Hebrew |
| Taz | Wild Animal, Thrid Born | Unisex | American |
| Tequila | An alcoholic liquor distilled from mescal. | Unisex | English |
| Tiger | Tiger | Unisex | English |
| Tiki | Maori figure representing an ancestor. A wooden or stone image of a Polynesian god. | Unisex | English |
| Tilly | Powerful battler | Unisex | Germanic |
| Tiny | Extremely small | Unisex | English |
| Toffee | A hard brown, chewy candy | Unisex | English |