| # | Name | Origin | Meaning | Gender | |
|---|---|---|---|---|---|
| 621 | Shan | Gaelic | old; wise. | M | |
| 622 | Sheridan | Gaelic | Bright. | M | |
| 623 | Sholto | Gaelic | Teal duck. | M | |
| 624 | SIaibhin | Gaelic | Mountain. | M | |
| 625 | Sim | Gaelic | Heard. | M | |
| 626 | Siolat | Gaelic | Teal duck. | M | |
| 627 | SIuaghan | Gaelic | Warrior. | M | |
| 628 | Skelley | Gaelic | Storyteller. | M | |
| 629 | Skelly | Gaelic | Storyteller. | M | |
| 630 | Slaven | Gaelic | Mountain. | M | |
| 631 | Slavin | Gaelic | Mountain. | M | |
| 632 | Sleven | Gaelic | Mountain. | M | |
| 633 | Slevin | Gaelic | Mountain. | M | |
| 634 | Slevyn | Gaelic | Mountain. | M | |
| 635 | Sloan | Gaelic | Warrior. | M | |
| 636 | Sloane | Gaelic | Warrior. | M | |
| 637 | Somerled | Gaelic | Asked of God. | M | |
| 638 | Somhairle | Gaelic | Asked of God. | M | |
| 639 | Steaphan | Gaelic | Crown; wreath. Variant of Stephen. | M | |
| 640 | Stiabhan | Gaelic | Gaelic form of Stepher. | M | |