| Name | Meaning | Gender | Origin |
|---|
| Rasta | | Unisex | Hebrew |
| Reeses | | Unisex | |
| Ricky | dominant or peaceful ruler | Male | English |
| Ringo | apple, peace be with you | Male | English |
| River | | Male | |
| Romeo | pilgrim to Rome | Male | Italian |
| Rug | | Unisex | Hebrew |
| Saki | Cape | Unisex | Japanese |
| Sam | to hear | Male | English |
| Sammie | | Unisex | |
| Samson | Bright sun
| Male | Hebrew |
| Sarge | Noncommissioned Army or Air Force rank | Male | |
| Sasquatch | has extra toes and hence is a bigfoot | Unisex | |
| Scruffy | Shabby or untidy | Unisex | |
| Sebastian | An august person | Male | Latin |
| Shaggy | Bushy and matted (hair), unkempt. | Unisex | |
| Silky | Soft as silk. | 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 | |
| Snuggles | To curl up closely, cuddle | Male | |
| Snuggles | To curl up closely, cuddle | Male | |
| Softy | | Unisex | |
| Sulley | | Unisex | |
| Sully | from the south meadow | Male | |