| Justine | | zhuy-STEEN (French), jus-TEEN (English) | French, English, Dutch, German | |
| Justus | | YUWS-tuws (German), JUS-təs (English) | German, Dutch, Late Roman | |
| Kai (1) | | KIE (German, Swedish, Finnish) | Frisian, German, Swedish, Norwegian, Danish, Finnish, Dutch | |
| Karel | | KAH-rəl (Dutch), KAH-rel (Czech) | Dutch, Czech, Slovene | |
| Karin | | KAH-rin (Swedish, German, Dutch), KAH-reen (Finnish), KER-ən (English), KAR-ən (English) | Swedish, Norwegian, Danish, German, Dutch, Finnish, English | |
| Kasper | | KAHS-per (Polish, Swedish), KAHS-pər (Dutch) | Polish, Dutch, Swedish, Norwegian, Danish | |
| Katelijn | | kah-tə-LIEN | Dutch | |
| Katelijne | | kah-tə-LIE-nə | Dutch | |
| Katinka | | kah-TING-kah (German) | German, Dutch | |
| Katja | | KAHT-yah (German, Dutch) | German, Swedish, Norwegian, Danish, Dutch, Slovene | |
| Katrien | | kaht-REEN | Dutch | |
| Katrijn | | kaht-RIEN | Dutch | |
| Katrina | | kə-TREE-nə (English), kaht-REE-nah (Dutch) | English, German, Swedish, Dutch | |
| Kees | | KAY:S | Dutch | |
| Kerneels | | - | Dutch | |