U.S. Citizenship Requirements for Naturalization

To qualify for US citizenship through naturalization, you generally need to be at least 18, hold a green card, have lived continuously in the United States for five years (three if you got your green card through marriage to a US citizen and remain in that marriage), be physically present here for at least half that time, read and speak basic English, pass a civics test, show good moral character, and take the Oath of Allegiance.¹² Each requirement comes from the Immigration and Nationality Act, and every one must be met at your interview and still be true when you take the oath.

Age, Green Card, and Time in the United States

You must be 18 or older when you file Form N-400.³ You must also be a lawful permanent resident. Federal law then requires five years of continuous residence in the United States immediately before filing, with at least 30 months (about 913 days) of physical presence inside the country during that stretch.⁴

If your green card came through marriage to a US citizen, the numbers shorten. You need three years of continuous residence and 18 months of physical presence, and you must have lived with your citizen spouse for that entire period, with your spouse holding citizenship the whole time.⁵

You also need to have lived in the state or USCIS district where you file for at least three months before submitting the application. One useful detail: you may file up to 90 days before you actually reach the five-year or three-year mark. USCIS will accept the early filing, though you won’t be eligible for the oath until the full period has passed.⁶

How Travel Abroad Affects Continuous Residence

Trips outside the country don’t automatically restart your clock, but the length of each absence matters. An absence of more than six months but less than a year creates a legal presumption that you broke continuous residence. You can rebut it by showing you kept your ties to the United States during the trip, but the burden is on you.⁷

An absence of one year or more automatically breaks continuous residence. There is no argument available. If it happens, you generally need to return and wait at least four years and one day before reapplying under the five-year track, so the long absence falls outside your new statutory period.⁸

If a job will take you overseas for a year or more, you may be able to protect your continuous residence by filing Form N-470 before you leave. This option is limited to permanent residents who have already lived in the United States for at least one uninterrupted year and whose work abroad falls into qualifying categories: US government employment, an American research institution, a US company engaged in foreign trade, a public international organization the United States belongs to, or a religious denomination with a US-based organization.⁹

Good Moral Character

You must show good moral character throughout the statutory period (five or three years) and continuing through the day you take the oath.¹⁰ Officers can look further back if earlier conduct raises concerns. This is the requirement that most often derails a case, because the standard reaches into more of your history than people expect.

Permanent Bars

A few offenses permanently disqualify you from establishing good moral character, no matter how long ago they happened. A murder conviction at any time is one. Any conviction for an aggravated felony committed on or after November 29, 1990 is another.¹¹ The immigration definition of “aggravated felony” is broader than the phrase suggests. It covers drug trafficking, firearms trafficking, money laundering over $10,000, fraud or tax evasion causing losses over $10,000, sexual abuse of a minor, and theft or violent crimes carrying a sentence of at least one year, among others.¹² Participation in Nazi persecution or genocide is also a permanent bar.

Conditional Bars

A longer list of offenses blocks good moral character only when they occur inside the statutory period. If enough time passes and the conduct falls outside your window, it won’t automatically bar you, though USCIS can still weigh it. The common conditional bars include:

Conviction or admission of a crime involving moral turpitude, with a narrow exception for a single petty offense
Any controlled substance violation, except simple possession of 30 grams or less of marijuana
Total incarceration of 180 days or more based on a conviction during the statutory period
False testimony under oath to obtain any immigration benefit
Two or more DUI convictions during the statutory period
Willful failure to support dependents
Two or more gambling convictions, deriving income principally from illegal gambling, or engaging in prostitution

¹³

Tax evasion, habitual drunkenness, polygamy, and human smuggling also fall into this group. Even conduct that never led to a conviction can count against you if it reflects poorly on your character.¹⁴

English and Civics Test

The naturalization test has two parts. For the English portion, a USCIS officer judges your speaking ability during the interview itself, and you read one sentence aloud from a set of three and write one sentence from a set of three. The standard is basic everyday English, not academic fluency.¹⁵

The civics test is oral. For applications filed on or after October 20, 2025, the officer draws 20 questions from a published list of 128 covering American history and government. You need at least 12 correct to pass. If you get 9 wrong, the test ends and you’ve failed that attempt.¹⁶

Age-Based Exemptions

Three exemptions ease the testing burden for long-term green card holders:

50/20: If you’re 50 or older with at least 20 years as a permanent resident, you skip the English test. You still take civics, in the language of your choice.
55/15: If you’re 55 or older with at least 15 years as a permanent resident, the same English exemption applies.
65/20: If you’re 65 or older with at least 20 years as a permanent resident, you skip English and take a simplified civics test drawn from just 20 of the 128 questions, in the language of your choice.

¹⁷¹⁸

If a physical, developmental, or mental health condition prevents you from learning English or civics, you can request a waiver by filing Form N-648, signed by a licensed medical professional who has evaluated you.¹⁹

Selective Service Registration for Male Applicants

Male applicants who lived in the United States between ages 18 and 26 were required to register with the Selective Service within 30 days of their 18th birthday. If you’re a man who missed that window, it can derail your case. USCIS treats a knowing and willful failure to register as evidence that you lack attachment to the Constitution and good moral character.²⁰

The consequence depends on how old you are when you apply. Under 26, you’re generally ineligible until you register. Between 26 and 31, USCIS will let you try to prove the failure to register wasn’t deliberate. Over 31, the failure falls outside the statutory period and won’t automatically block you. Men who did not live in the United States between 18 and 26, or who held lawful nonimmigrant status for that entire stretch, weren’t required to register in the first place.

If you should have registered but didn’t, request a status information letter from the Selective Service System before filing your N-400. You’ll likely need to include a written explanation.²¹

The Oath of Allegiance

Every applicant must be willing to take the Oath of Allegiance at a ceremony. The oath commits you to supporting the US Constitution, renouncing allegiance to foreign governments, and bearing arms or performing civilian national service if the law requires it.²² You aren’t a citizen until you actually recite the oath. Passing the interview alone doesn’t do it.

The renunciation language worries many applicants who want to keep their original nationality. In practice, US law doesn’t force you to choose. The oath expresses your commitment to the United States, but the US government does not revoke your foreign citizenship. Whether you can keep the other nationality depends on that country’s laws, not American ones.²³

Reduced Requirements for Military Service

Members of the US Armed Forces qualify for citizenship under looser rules. Under INA Section 328, if you’ve served honorably for at least one year total, you can apply while still serving or within six months of an honorable discharge. You must be a lawful permanent resident at the interview, and you still need to pass the English and civics tests and show good moral character for the five years before filing.²⁴

Under INA Section 329, service members who served during a designated period of hostility (active since September 11, 2001) get even more favorable terms. There is no minimum service length beyond one day of active duty. You don’t need to be a permanent resident, as long as you were physically present in the United States or a qualifying territory when you enlisted. The good moral character period drops to one year before filing. And there is no filing fee for military applicants.²⁴

When Naturalization Isn’t the Right Path

Some people born abroad don’t need to naturalize because they’re already citizens. If you acquired US citizenship at birth through a US citizen parent, or became a citizen before age 18 when a parent naturalized, you don’t file Form N-400. You file Form N-600 to obtain a Certificate of Citizenship documenting the status you already have.²⁵ A parent or legal guardian can file for a minor child. If the parent who transmitted citizenship later dies or divorces, that doesn’t undo the child’s citizenship as long as it was acquired first.

1
U.S. Citizenship and Immigration Services. I Am a Lawful Permanent Resident of 5 Years
2
Office of the Law Revision Counsel. 8 USC 1430 – Married Persons and Employees of Certain Nonprofit Organizations
3
USAGov. Become a U.S. Citizen Through Naturalization
4
U.S. Citizenship and Immigration Services. Chapter 4 – Physical Presence
5
U.S. Citizenship and Immigration Services. Continuous Residence and Physical Presence Requirements for Naturalization
6
U.S. Citizenship and Immigration Services. Chapter 6 – Jurisdiction, Place of Residence, and Early Filing
7
Office of the Law Revision Counsel. 8 USC 1427 – Requirements of Naturalization
8
U.S. Citizenship and Immigration Services. Chapter 3 – Continuous Residence
9
U.S. Citizenship and Immigration Services. N-470, Application to Preserve Residence for Naturalization Purposes
10
U.S. Citizenship and Immigration Services. Chapter 9 – Good Moral Character
11
U.S. Citizenship and Immigration Services. Permanent Bars to Good Moral Character
12
Office of the Law Revision Counsel. 8 USC 1101 – Definitions
13
U.S. Citizenship and Immigration Services. Chapter 5 – Conditional Bars for Acts in Statutory Period
14
U.S. Citizenship and Immigration Services. USCIS Policy Manual Volume 12 Part F Chapter 1 – Purpose and Background
15
U.S. Citizenship and Immigration Services. The Naturalization Interview and Test
16
Federal Register. Notice of Implementation of 2025 Naturalization Civics Test
17
U.S. Citizenship and Immigration Services. Exceptions and Accommodations
18
U.S. Citizenship and Immigration Services. Civics Questions for the 65/20 Exemption
19
U.S. Citizenship and Immigration Services. Medical Certification for Disability Exceptions
20
U.S. Citizenship and Immigration Services. Chapter 7 – Attachment to the Constitution
21
Selective Service System. Men 26 and Older
22
U.S. Citizenship and Immigration Services. Naturalization Oath of Allegiance to the United States of America
23
U.S. Department of State. Dual Nationality
24
U.S. Citizenship and Immigration Services. Naturalization Through Military Service
25
U.S. Citizenship and Immigration Services. N-600, Application for Certificate of Citizenship Frequently Asked Questions