| # | Name | Origin | Meaning | Gender | |
|---|---|---|---|---|---|
| 621 | Llewelyn | Welsh | Variant of Llewellyn: Leader. Lion-like. | M | |
| 622 | Llinos | Welsh | Linnet. | F | |
| 623 | Lloyd | Welsh | Grey. One with grey hair. In common use as both a surname and first name. | M | |
| 624 | Lludd | Welsh | From London. | M | |
| 625 | Llundein | Welsh | From London. | M | |
| 626 | Llwybyr | Welsh | Legendary son of Caw. | M | |
| 627 | Llwyd | Welsh | Legendary son of Kil Coed 'one with gray hair'. | M | |
| 628 | Llwydeu | Welsh | Legendary son of Nwython. | M | |
| 629 | Llwyr | Welsh | Legendary son of LIwyryon. | M | |
| 630 | Llyn | Welsh | From the lake. | M | |
| 631 | Llyr | Welsh | From the sea. | M | |
| 632 | Llyweilun | Welsh | Lion. | M | |
| 633 | Lowri | Welsh | Welsh form of Laura, meaning laurel. | F | |
| 634 | Luc | Welsh | Welsh form of Luke 'light'. | M | |
| 635 | Lug | Welsh | Welsh form of Luke 'light'. | M | |
| 636 | Lyn | Welsh | Diminutive of Llewellyn: Leader. Lion-like. | M | |
| 637 | Lynelle | Welsh | Variant of ancient Welsh given name Eluned: From 'cilun' meaning idol. | F | |
| 638 | Lynessa | Welsh | Variant of ancient Welsh given name Eluned: From 'cilun' meaning idol. | F | |
| 639 | Lynette | Welsh | Variant of ancient Welsh given name Eluned: From 'cilun' meaning idol. | F | |
| 640 | Lynnet | Welsh | Variant of ancient Welsh given name Eluned: From 'cilun' meaning idol. | F | |