| # | Name | Origin | Meaning | Gender | |
|---|---|---|---|---|---|
| 601 | Ronnell | Gaelic | Rules with counsel. Form of Ronald from Reynold. | M | |
| 602 | Ronnie | Gaelic | Rules with counsel. Form of Ronald from Reynold. | M | |
| 603 | Ronny | Gaelic | Rules with counsel. Form of Ronald from Reynold. | M | |
| 604 | Rooney | Gaelic | Red haired. | M | |
| 605 | Rory | Gaelic | Red; ruddy. | M | |
| 606 | Rourke | Gaelic | An ancient given name adopted as an Irish clan name. Surname. | M | |
| 607 | Rowan | Gaelic | Red. Rowan tree (a type of ash tree). Famous Bearer: actor Rowan Atkinson. | M | |
| 608 | Roy | Gaelic | Red. | M | |
| 609 | Royal | Gaelic | Red. | M | |
| 610 | Royall | Gaelic | Red. | M | |
| 611 | Royan | Gaelic | Red-haired; red. | M | |
| 612 | Ruailidh | Gaelic | Famous ruler. | M | |
| 613 | Ruanaidh | Gaelic | Red haired. | M | |
| 614 | Ryan | Gaelic | Little king. | M | |
| 615 | Scully | Gaelic | Town crier. | M | |
| 616 | Seamus | Gaelic | Form of James. Supplanter. | M | |
| 617 | Seorus | Gaelic | Farmer. | M | |
| 618 | Seosamh | Gaelic | He shall add. | M | |
| 619 | Seumas | Gaelic | Supplanter. | M | |
| 620 | Sguelaiche | Gaelic | Storyteller. | M | |