| Katharina | | kah-tah-REE-nah (German, Swedish) | German, Swedish, Norwegian, Danish | |
| Kathrine | | - | Danish, Norwegian | |
| Katja | | KAHT-yah (German, Dutch) | German, Swedish, Norwegian, Danish, Dutch, Slovene | |
| Katrine | | kaht-REE-ne (Danish) | Danish, Norwegian | |
| Kay (3) | | KIE (Swedish) | Frisian, German, Swedish, Norwegian, Danish | |
| Keld | | - | Danish | |
| Kennet | | - | Swedish, Norwegian, Danish | |
| Kenneth | | KEN-ith (Scottish, English) | Scottish, English, Swedish, Norwegian, Danish | |
| Kevin | | KEV-in (English) | English, Irish, French, German, Dutch, Swedish, Norwegian, Danish | |
| Kim (2) | | KEEM (Finnish) | Danish, Swedish, Norwegian, Finnish | |
| Kirsten | | KEER-sten (Danish, Norwegian), KUR-stən (English) | Danish, Norwegian, English | |
| Kirstine | | - | Danish | |
| Kjeld | | - | Danish | |
| Klara | | KLAH-rah (German, Russian, Polish) | Swedish, Norwegian, Danish, Icelandic, German, Russian, Ukrainian, Polish, Slovene, Croatian | |
| Klaus | | KLOWS (German, Finnish) | German, Danish, Norwegian, Finnish | |