Who Qualifies for U.S. Naturalization? Eligibility Requirements Explained

Before applying for U.S. citizenship, you must meet specific USCIS eligibility requirements. Learn the residency, age, language, and good moral character rules that determine whether you're ready to file your N-400.

By Marcus G. Bastawros, MBA · Published 2026-05-03 · Updated 2026-05-03

Sources and corrections: read our editorial standards and corrections policy.

U.S. naturalization is the legal process by which a non-citizen becomes a U.S. citizen. Not every permanent resident is immediately eligible. USCIS requires applicants to meet a specific set of conditions before filing Form N-400, Application for Naturalization. Understanding those requirements helps you know exactly when you're eligible — and avoid filing too early, which wastes money and causes delays.

You Must Be a Lawful Permanent Resident

You must hold a green card (lawful permanent resident status) before applying for naturalization. You cannot naturalize directly from a visa or temporary status. If you recently received your green card, the clock for the residency requirement starts from the date your permanent residence was granted — not the date you entered the country.

The 5-Year Continuous Residence Rule

For most applicants, you must have been a lawful permanent resident for at least 5 years before filing. During those 5 years, you must have been physically present in the United States for at least 30 months (half of the 5-year period). Extended trips outside the U.S. (generally 6 months or more in a single trip) can disrupt your continuous residence and may reset part of your clock.

The 3-Year Rule for Married U.S. Citizens

If you are married to and living with a U.S. citizen, the residence requirement drops to 3 years — provided you have been a permanent resident for 3 years and have been married to the same U.S. citizen for the entire 3-year period. The physical presence requirement also drops proportionally to 18 months out of the 3 years.

Age Requirement

You must be at least 18 years old to file Form N-400 on your own. Minor children of U.S. citizens may automatically acquire citizenship under certain circumstances through the Child Citizenship Act of 2000, but that is a separate process and does not require filing an N-400.

Continuous Residence During the Application Period

You must also maintain continuous residence in the United States while your application is pending. This means you should not take long trips abroad (typically 6 months or more) after filing your N-400 without understanding the potential impact on your application.

Good Moral Character

USCIS requires that you have been a person of good moral character during the statutory period (the 5 or 3 years before filing, depending on your category). In practice, this means reviewing your criminal history carefully. Certain criminal convictions — particularly aggravated felonies — can permanently bar you from naturalization. USCIS also looks at tax filings, child support obligations, and whether you've claimed to be a U.S. citizen when you were not.

English Language Ability

Most applicants must demonstrate the ability to read, write, speak, and understand basic English. The English test is administered at your naturalization interview. Exceptions apply for applicants who are 50 or older with 20 or more years of permanent residence (the '50/20 exception'), or 55 or older with 15 or more years of permanent residence (the '55/15 exception').

The Civics Knowledge Requirement

All applicants — including those exempt from the English requirement — must pass the USCIS civics test. The test consists of 20 questions drawn from the official 128-question bank; 12 correct answers are required to pass. You'll find all 128 official civics questions on the USCIS website, and practicing them is the most direct way to prepare.

Attachment to the Constitution

You must declare that you support the principles of the U.S. Constitution and are willing to take the Oath of Allegiance to the United States. The Oath requires renouncing allegiance to foreign states and being willing to defend the United States. If your beliefs or prior conduct are inconsistent with the Oath, it may affect your eligibility.

Check your readiness · Try the practice game · Study with Tito · Rehearse with Officer Marcus · Compare free and Premium access