| ljusstråle | streamer |
| ljusstyrka | luminosity |
| ljust | brightly |
| ljuster | gaff |
| Ljusterapi | Light therapy |
| ljusvåg | light-wave |
| ljusår | light-year |
| Ljutomer | Ljutomer |
| ljuv | delicious |
| ljuva ord | sweet nothings |
| ljuvlig | delightful |
| ljuvlighet | loveliness |
| ljuvligt | wonderfully |
| Llandovery | Llandovery epoch |
| Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch | Llanfairpwllgwyngyll |
| Llangollen | Llangollen |
| Lleida | Lleida |
| Lleu Llaw Gyffes | Lleu Llaw Gyffes |
| Lleyn | Llŷn Peninsula |
| Lleyton Hewitt | Lleyton Hewitt |
| Llobregat | Llobregat |
| Lloque Yupanqui | Lloque Yupanqui |
| LLR | Lunar laser ranging experiment |
| Lluís Domènech i Montaner | Lluís Domènech i Montaner |
| Llyr | Lir |
| Llywelyn den siste | Llywelyn the Last |
| lo | lynx |
| Lo-fi | Low fidelity |
| Loa | Loa River |
| lob | lobe |
| lobfenig | coelacanth |
| Lobfeniga fiskar | Sarcopterygii |
| lobotomi | lobotomy |
| Local Area Network | Local area network |
| Local Interconnect Network | Local Interconnect Network |
| Locarno | Locarno |
| Locarnofördraget | Locarno Treaties |
| Location-scouting | Location scouting |
| Loch Linnhe | Loch Linnhe |
| Loch Lomond | Loch Lomond |
| Loch Ness | Loch Ness |
| Loch Ness-odjuret | Loch Ness Monster |
| Lochgilphead | Lochgilphead |
| Lochteå | Lohtaja |
| lock | cover |
| lock i pannan | forelock |
