| # | Name | Origin | Meaning | Gender | |
|---|---|---|---|---|---|
| 321 | Ingmar | Norse | Famous son. | M | |
| 322 | Ingolf | Norse | Ing's wolf. | M | |
| 323 | Ingram | Norse | Ing's raven. | M | |
| 324 | Isleif | Norse | Brother of Isrod. | M | |
| 325 | Isolf | Norse | Son of Hrani. | M | |
| 326 | Isrod | Norse | Brother of Isleif. | M | |
| 327 | Ivor | Norse | Lord. A variant of the name Ifor. Famous Bearer: Composer Ivor Novello (1893-1951). | M | |
| 328 | Jolgeir | Norse | Brother of Radorm. | M | |
| 329 | Jormungand | Norse | The serpent who encircles the earth. | M | |
| 330 | Jorund | Norse | Son of Hrafn the Foolish. | M | |
| 331 | Kalf | Norse | Half son of Asgeir. | M | |
| 332 | Kalman | Norse | A man from Ireland. | M | |
| 333 | Kare | Norse | Tremendous. | M | |
| 334 | Kari | Norse | Tremendous. | M | |
| 335 | Karli | Norse | Manly. | M | |
| 336 | Karr | Norse | From the marsh. | M | |
| 337 | Keldan | Norse | From the spring. | M | |
| 338 | Kell | Norse | From the spring. | M | |
| 339 | Kelsey | Norse | From the ship's island. | M | |
| 340 | Kelsig | Norse | From the ship's island. | M | |