| Name | Gender | Pronounced | Usage | Popularity |
|---|---|---|---|---|
| Kadri | KAHD-rree | Estonian | ||
| Kaia | - | Norwegian, Estonian | ||
| Kaisa | KIE-sah (Finnish) | Finnish, Estonian | ||
| Kaja (1) | KAH-yah (Swedish, Estonian) | Norwegian, Danish, Swedish, Estonian, Slovene | ||
| Kaja (3) | KAH-yah | Estonian | ||
| Kalev (1) | - | Estonian | ||
| Kalju | - | Estonian | ||
| Katariina | KAH-tah-ree:-nah (Finnish) | Finnish, Estonian | ||
| Kati | KAH-tee (Finnish) | Finnish, Estonian, Hungarian | ||
| Katrin | kah-TREEN (German, Swedish) | German, Swedish, Estonian | ||
| Koit | - | Estonian | ||
| Kristiina | KREES-tee:-nah (Finnish) | Finnish, Estonian | ||
| Kristjan | - | Estonian, Slovene |