| Ivan | | ee-VAHN (Russian, Ukrainian), IE-vən (English) | Russian, Bulgarian, Ukrainian, Belarusian, Serbian, Croatian, Czech, Slovak, Macedonian, Slovene, En | |
| Ivanna | | - | Russian (Rare) | |
| Jekaterina | | ye-kah-tye-REE-nah, ee-kah-tee-REE-nah | Russian | |
| Julia | | JOO-lee-ə (English), YOO-lee-ah (German, Swedish, Danish, Finnish), HOO-lyah (Spanish), YUWL-yah (Polish), YOO-lee-yah (Russian), YOO:-lee-ah (Ancient Roman) | English, German, Swedish, Norwegian, Danish, Dutch, Spanish, Polish, Finnish, Russian, Ukrainian, An | |
| Juliya | | YOO-lee-yah (Russian) | Russian, Ukrainian | |
| Karina | | kah-REE-nah (Swedish, Polish, German, Russian), kə-REE-nə (English) | Swedish, Danish, Norwegian, Polish, German, Russian, English | |
| Karp | | KAHRP | Russian | |
| Katenka | | - | Russian | |
| Katerina | | - | Macedonian, Russian, Bulgarian, Greek, Late Roman | |
| Katia | | KAH-tyah | Russian | |
| Katya | | KAH-tyah | Russian | |
| Kazimir | | kah-zee-MEER (Russian) | Russian, Medieval Slavic | |
| Kesha | | - | Russian | |
| Khariton | | - | Russian | |
| Kir | | KEER | Russian | |