I have lived in Korea for many years and want to become a Korean citizen?

Naturalization generally requires 5 years of continuous residence (less for marriage or special cases), a legal stay status, proof of livelihood, good conduct, and passing a naturalization test plus interview on Korean language and society, which the KIIP program can exempt you from. Korea has historically required renouncing your original citizenship, but there are exceptions where dual citizenship is allowed (for example marriage-based and certain talent cases) if you pledge not to exercise the foreign nationality in Korea. The process takes a long time, often over a year, so gather documents early and check the current rules with the Korea Immigration Service.