| Name | Gender | Pronounced | Usage | Popularity |
|---|---|---|---|---|
| Isidoros | - | Ancient Greek | ||
| Isocrates | - | Ancient Greek (Latinized) | ||
| Isokrates | - | Ancient Greek | ||
| Kallias | - | Ancient Greek | ||
| Kallikrates | - | Ancient Greek | ||
| Kallisto | - | Greek Mythology, Ancient Greek | ||
| Kallistos | - | Ancient Greek | ||
| Kallistrate | - | Ancient Greek | ||
| Karpos | - | Ancient Greek, Biblical Greek | ||
| Kassandra | kə-SAN-drə (English) | Greek Mythology, Ancient Greek, English (Modern) | ||
| Kassandros | - | Ancient Greek | ||
| Kleisthenes | - | Ancient Greek | ||
| Kleitos | - | Ancient Greek | ||
| Kleon | - | Ancient Greek | ||
| Kleopatra | - | Ancient Greek |