| Silvestra | | - | Italian, Slovene | |
| Silvia | | SEEL-vyah (Italian), SEEL-byah (Spanish) | Italian, Spanish, Portuguese, Romanian, Slovak, English, German, Late Roman, Roman Mythology | |
| Silvija | | - | Croatian, Slovene | |
| Simon | | SIE-mən (English), see-MAWN (French), ZEE-mawn (German), SEE-mawn (Dutch) | English, French, Swedish, Norwegian, Danish, German, Dutch, Hungarian, Slovene, Romanian, Macedonian | |
| Simona | | - | Italian, Czech, Slovak, Romanian, Lithuanian, Slovene, Bulgarian, Macedonian | |
| Simone (1) | | see-MON (French) | French, English | |
| Simonette | | - | English (Rare) | |
| Simonides | | - | Ancient Greek | |
| Sinclair | | sin-KLER | English (Rare) | |
| Sindri | | - | Norse Mythology, Ancient Scandinavian, Icelandic | |
| Sindy | | SIN-dee | English (Rare) | |
| Sinjin | | - | English (Rare) | |
| Siran | | - | Armenian | |
| Siranush | | - | Armenian | |
| Sirvard | | - | Armenian | |