The most common pathway for long-term Green Card holders to become U.S. citizens is naturalization. This process typically involves filing Form N-400, Application for Naturalization, passing an English language and civics test, and completing an interview with a United States Citizenship and Immigration Services (USCIS) officer. Successful applicants then participate in an Oath of Allegiance ceremony.

Expedited pathways exist for certain groups and situations.

Citizenship through Marriage (Spouses of U.S. citizens): If the Green Card holder has been married to and living with the same U.S. citizen for the past three years, and the spouse has been a U.S. citizen for at least these three years, they can apply for naturalization.
Citizenship through Military Service: Green Card holders who serve in the U.S. military might be eligible for expedited citizenship.
Citizenship for Refugees and Asylees: Long-term Green Card holders who initially entered the U.S. as refugees or asylees may be eligible for citizenship five years after their date of entry.
Citizenship through Parents: Adult Green Card holders may be eligible for citizenship if they have at least one parent who is a U.S. citizen by birth or naturalization.