| Name | Gender | Pronounced | Usage | Popularity |
|---|---|---|---|---|
| KÁJa | - | Czech | ||
| KajetÁN | - | Czech, Slovak, Hungarian | ||
| Kamil (2) | KAH-meel (Polish) | Czech, Slovak, Polish | ||
| Kamila | kah-MI-lah (Czech, Slovak), kah-MEE-lah (Polish) | Czech, Slovak, Polish | ||
| Karel | KAH-rəl (Dutch), KAH-rel (Czech) | Dutch, Czech, Slovene | ||
| KarolÍNa | - | Czech | ||
| KateŘIna | - | Czech | ||
| Katka | KAHT-kah | Czech, Slovak | ||
| KazimÍR | - | Czech, Slovak, Hungarian | ||
| KlÁRa | - | Hungarian, Czech, Slovak | ||
| Klaudie | - | Czech | ||
| Klement | - | Czech, Slovak | ||
| KonrÁD | - | Hungarian, Czech, Slovak | ||
| KornÉLie | - | Czech | ||
| Kornel | KAWR-nel (Polish) | Polish, Czech, Slovak |