| Country | Nationality |
| Indian Ocean | void |
| Indonesia | noun: Indonesian(s) adjective: Indonesian |
| Iran | noun: Iranian(s) adjective: Iranian |
| Iraq | noun: Iraqi(s) adjective: Iraqi |
| Ireland | noun: Irishman(men), Irishwoman(women), Irish (collective plural) adjective: Irish |
| Isle of Man | noun: Manxman (men), Manxwoman (women) adjective: Manx |
| Israel | noun: Israeli(s) adjective: Israeli |
| Italy | noun: Italian(s) adjective: Italian |
| Jamaica | noun: Jamaican(s) adjective: Jamaican |
| Jan Mayen | void |
| Japan | noun: Japanese (singular and plural) adjective: Japanese |
| Jersey | noun: Channel Islander(s) adjective: Channel Islander |
| Jordan | noun: Jordanian(s) adjective: Jordanian |
| Kazakhstan | noun: Kazakhstani(s) adjective: Kazakhstani |
| Kenya | noun: Kenyan(s) adjective: Kenyan |
| Kiribati | noun: I-Kiribati (singular and plural) adjective: I-Kiribati |
| Korea, North | noun: Korean(s) adjective: Korean |
| Korea, South | noun: Korean(s) adjective: Korean |
| Kosovo | noun: Kosovar (Albanian), Kosovac (Serbian) adjective: Kosovar (Albanian), Kosovski (Serbian) note: Kosovan, a neutral term, is sometimes also used as a noun or adjective |
| Kuwait | noun: Kuwaiti(s) adjective: Kuwaiti |
| Kyrgyzstan | noun: Kyrgyzstani(s) adjective: Kyrgyzstani |