| Name | Meaning | Gender | Origin |
|---|
| Santa | Saintlike | Unisex | Spanish |
| Satan | The Devil and adversary of God | Unisex | English |
| Scamp | A mischievous youngster | Unisex | English |
| Scamper | | Unisex | Hebrew |
| Scout | Observer | Unisex | American English |
| Scuttle | | Unisex | Hebrew |
| Sea | Mercy in god | Unisex | Hebrew |
| Serena | Composed | Female | Latin |
| Seymore | Our cat who likes to hide that we want to see more of | Unisex | English |
| Shadow | Shadow | Unisex | English |
| Shaggy | Bushy and matted (hair), unkempt. | Unisex | English |
| Shelby | A place where willows grow | Female | American English |
| Shelly | Clearing near a ledge | Unisex | English |
| Shiloh | Gift for him | Unisex | Hebrew |
| Shorty | Of less than average size | Unisex | English |
| Skylar | Guarded | Female | Dutch |
| Sleepy | | Unisex | Hebrew |
| Slinkster | | Unisex | Hebrew |
| Slinky | | Unisex | Hebrew |
| Smiley | | Unisex | Hebrew |
| Smokey | A grayish blue colour. Slang for highway patrol officer | Unisex | English |
| Smoky | | Unisex | Hebrew |
| Smudge | A blotch or smear | Unisex | English |
| Sneezy | | Unisex | Hebrew |
| Snicker | | Unisex | Hebrew |
| Sniff | A short inhale through the nose. To savour or investigate a smell. | Unisex | English |
| Snoopy | | Unisex | Hebrew |
| Snowball | | Unisex | Hebrew |
| Snowy | Covered with snow | Female | English |
| Snuffles | | Unisex | Hebrew |