| Si raj | A name meaning brilliant light. |
| Siaf | One who is a sharp sword of God. |
| Siamu | A character from Shahnameh. |
| Siarles | Variant of the name Charles, meaning free man |
| Sicga | An ancient Germanic name. |
| Siddigue | True Friend To Confirm The Truth |
| Siediu | A name meaning one who is very lucky. |
| Siem | A name meaning to listen or to hear. |
| Sig | Victorious Peace |
| Sigebehrt | One who is bright and bold. |
| Sigurdur | Victorious guardian, a Scandinavian name with mythological roots |
| Sihath | A person with the heart of a lion. |
| Sihina | A name that translates to dream. |
| Sijaj | The Rapid Flow Of Water |
| Siler | Peaceful and serene, a variant of the name Silas |
| Sillan | Gift of the gods, a variant of the name Sillan |
| Silven | Forest or woods, a variant of the name Silvan |
| Silviano | Forest dweller, a Latin name with natural connotations |
| Simbiah | Gift of God, a variant of the name Simba |
| Simecek | A surname meaning a small family unit. |
| Simhaksh | One with lionlike eyes. |
| Simione | God has heard the prayer. |
| Sinann | One who is sharp and focused. |
| Sindre | Victorious protector, a Scandinavian name with mythological roots |
| Sinhue | Gift of the gods, a variant of the name Sinhue |
| Sinqua | Derived from the Latin word for 'five' or 'quintessence'. |
| Sinyura | A name meaning a noble lady or dame. |
| Siraj Ud Dola | Arabic name meaning 'light of the moon' or 'moonlight'. |
| Sire | French name meaning 'lord' or 'master'. |
| Sisamila | Sanskrit name meaning 'beautiful' or 'lovely'. |
| Sithija | Born from the earth or soil. |
| Sithil | One who is calm and peaceful. |
| Sithmina | A gem of pure, calm thoughts. |
| Sithmuka | One with a peaceful expression. |
| Sithuka | One who brings peaceful vibes. |
| Sithumina | A precious gem of the mind. |
| Sitka | Derived from the Tlingit word for 'people of the marsh'. |
| Sivsankar | The Supreme Spirit |
| Sixte | A name meaning the sixth child. |
| Siyum | A name meaning a gentle breeze. |