| Kiril | | - | Bulgarian, Macedonian | |
| Kiro | | - | Macedonian | |
| Kliment | | klee-MYENT (Russian) | Russian, Ukrainian, Bulgarian, Macedonian | |
| Klimentina | | - | Macedonian | |
| Konstantin | | KAWN-stahn-teen (German), kahn-stahn-TEEN (Russian) | German, Hungarian, Russian, Serbian, Bulgarian, Macedonian | |
| Kostadin | | - | Bulgarian, Macedonian | |
| Kristijan | | KREES-tee-yahn (Serbian, Croatian) | Serbian, Croatian, Slovene, Macedonian | |
| Ksenija | | - | Serbian, Croatian, Macedonian, Slovene | |
| Kuzman | | - | Bulgarian, Serbian, Macedonian | |
| Lazar | | LAH-zahr (Russian, Serbian, Croatian) | Russian, Bulgarian, Serbian, Croatian, Macedonian | |
| Lidija | | - | Slovene, Croatian, Serbian, Macedonian | |
| Liljana | | - | Macedonian | |
| Ljuba | | LYOO-bah (Serbian, Croatian) | Serbian, Croatian, Czech, Slovene, Macedonian | |
| Ljube | | - | Macedonian | |
| Ljuben | | - | Macedonian | |