| Name | Meaning | Gender | Origin |
|---|
| Ralph | Red wolf
| Male | English |
| Rambo | | Male | |
| Rebel | One that resists of defies authority | Male | Word |
| Rex | after the Rex Banner character in The Simpsons cartoons | Male | Latin |
| Ripper | | Unisex | |
| River | | Male | |
| Rocky | rest | Male | English |
| Romeo | pilgrim to Rome | Male | Italian |
| Roo | | Unisex | Hebrew |
| Rusty | Covered in rust - a brownish red colour. | Unisex | |
| Sam | to hear | Male | English |
| Sammy | Hebrew, told by God | Male | English |
| Sandy | Abbreviation of Alexander defender of man.
| Male | Scottish |
| Schooner | | Unisex | Hebrew |
| Scooter | One who goes suddenly and speedily. | Male | |
| Scruffy | Shabby or untidy | Unisex | |
| Sebastian | An august person | Male | Latin |
| Shamrock | | Unisex | |
| Sheeba | after the cat food | Unisex | |
| Shmoo | | Unisex | Hebrew |
| Simba | lion | Male | Swahili |
| Simba | from The Lion King | Male | Swahili |
| 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 | |