| Kalina | | - | Bulgarian, Macedonian, Polish | |
| Karolina | | kah-raw-LEE-nah (Polish), kah-ro-LEE-nah (Swedish, German) | Polish, Swedish, Norwegian, Danish, Hungarian, Slovene, Croatian, Macedonian, Lithuanian, German | |
| Katerina | | - | Macedonian, Russian, Bulgarian, Greek, Late Roman | |
| Katina | | - | Greek, Macedonian | |
| Kire | | - | Macedonian | |
| 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 | |