Does Guam Have Income Tax? Rates, Residency, and Filing

Yes, Guam has an income tax. The territory runs what’s known as a mirror tax system: federal law adopts the U.S. Internal Revenue Code as Guam’s local tax code, so the rates, brackets, and deductions match the ones the IRS uses on the mainland. Whether you pay Guam, the IRS, or both comes down to whether you qualify as a bona fide resident of the territory.

How Guam’s Mirror Tax Works

Under 48 U.S.C. § 1421i, the Guam Territorial Income Tax adopts the federal Internal Revenue Code as local law.¹ Wherever the federal code says “United States,” Guam’s version reads “Guam.” Wherever it says “Secretary of the Treasury,” Guam’s version reads “Governor.” Because of this structural swap, the territory automatically inherits every change Congress makes to federal tax law without writing its own code.

One local wrinkle: the Guam Legislature may impose a surcharge of up to 10 percent on top of a taxpayer’s annual territorial income tax.¹ Depending on local legislation, a Guam taxpayer’s total liability could therefore exceed what someone earning the same income owes on the mainland.

2026 Rates and Standard Deductions

Because Guam mirrors federal law, its 2026 brackets and deductions are the same as the IRS figures. Marginal rates run from 10 percent to 37 percent:²

10% on income up to $12,400 single ($24,800 married filing jointly)
12% on income over $12,400 ($24,800 jointly)
22% on income over $50,400 ($100,800 jointly)
24% on income over $105,700 ($211,400 jointly)
32% on income over $201,775 ($403,550 jointly)
35% on income over $256,225 ($512,450 jointly)
37% on income over $640,600 ($768,700 jointly)

The 2026 standard deduction is $16,100 for single filers, $32,200 for married couples filing jointly, and $24,150 for heads of household.²

Who Counts as a Bona Fide Resident of Guam

Your filing obligations turn on bona fide residency under Treasury Regulation § 1.937-1. You have to pass three separate tests for the tax year: a presence test, a tax home test, and a closer connection test. Failing any one of them means you are not a bona fide resident.³

Presence Test

You can satisfy the presence test in any one of four ways:

You were physically present in Guam for at least 183 days.
You were present in the United States for no more than 90 days.
Your earned income from U.S. sources was no more than $3,000 total, and you spent more days in Guam than in the United States.
You had no significant connection to the United States during the year.

Days are counted broadly. If you were physically in Guam at any point during a calendar day, that day counts. Days spent outside the territory for qualifying medical treatment or during a federally declared disaster also count as Guam days.

Tax Home and Closer Connection

The tax home test looks at where your main place of business or employment is located. If you work primarily in Guam, this test is usually straightforward. The closer connection test looks at personal ties: your permanent home, where your vehicle is registered, where you vote, and similar factors.

Filing as a Bona Fide Resident

If you are a bona fide resident of Guam for the entire tax year, you file one return with the Guam Department of Revenue and Taxation on Form 1040-GU, the territorial version of the federal 1040. You report your worldwide income on that return, not just Guam-source income.⁴ When you tally payments, include tax withheld or paid to either Guam or the United States, plus any estimated payments to either jurisdiction.

File properly with Guam and pay your territorial tax in full, and you generally do not need to file a separate return with the IRS. The main exception is self-employment.⁴

Self-Employment Adds an IRS Filing

Even if you owe nothing else to the United States, you must file Form 1040-SS with the IRS when your net self-employment earnings from a Guam trade or business reach $400 or more.⁴ Form 1040-SS reports the income to the United States and calculates the Social Security and Medicare taxes owed on it.⁵ It is separate from your Guam territorial return, so you may need to file both.

Form 1040-SS is normally due April 15 for calendar-year filers, but bona fide Guam residents get an automatic two-month extension to June 15 by attaching a statement confirming their territorial residency.⁶ You can request an additional four-month extension beyond that if you need it.

Non-Residents Earning Guam-Source Income

If you are a U.S. citizen or resident alien who is not a bona fide resident of Guam but earned money from Guam sources, you file your return with the IRS, not with Guam. Report your worldwide income on your U.S. return and credit any tax withheld or paid to Guam.⁴

You may also have to attach Form 5074, which allocates part of your tax to Guam. It is required when all three of the following apply:

You file a U.S. income tax return.
Your adjusted gross income is $50,000 or more.
At least $5,000 of the gross income on your return comes from Guam sources.

Failing to provide the required Form 5074 information can trigger a $1,000 penalty for each failure, unless you show the omission was due to reasonable cause rather than willful neglect.

Coordination When Your Income Comes From Both Places

Treasury Regulation § 1.935-1 decides which jurisdiction gets your return when your income spans both. Bona fide residents of Guam file with the Guam Department of Revenue and Taxation. U.S. residents file with the IRS.⁷

For married couples filing jointly, the return goes to whichever jurisdiction would apply to the spouse with the higher adjusted gross income, as if the spouses had filed separately.⁷ Wherever you file, you report your entire worldwide income on a single return and get credit for tax already withheld or paid to the other jurisdiction, so the same income is not taxed twice.

Military Members Stationed in Guam

Active-duty service members get special treatment. If you were not already a bona fide resident of Guam before your assignment, being stationed there solely in compliance with military orders does not make you one.⁴ You keep filing with the IRS based on your legal state of residence, and the Servicemembers Civil Relief Act generally prevents Guam from taxing your military pay when the territory is not your legal domicile.

The reverse also holds. If you were a bona fide resident of Guam before entering active duty, being deployed away from the island under military orders does not end that residency, and you continue filing with the Guam Department of Revenue and Taxation.⁴ Military pay is generally sourced to your state of legal residence, so where it gets taxed depends on whether you claim Guam or a state as your domicile.

Reporting a Move To or From Guam

If you move to or from Guam and your worldwide gross income exceeds $75,000, you must file IRS Form 8898 for the year the change happens. It is due by your Form 1040 deadline, including extensions.⁸

The IRS also applies look-back and look-forward rules. To claim bona fide residency for the year you move to Guam, you generally must remain a bona fide resident for the three tax years immediately after.⁸ If you move away, you must have been a bona fide resident for the three tax years immediately before, and you cannot requalify as one in the three years after you leave.

Deadlines and Estimated Payments

Guam’s territorial return follows the federal calendar. For tax year 2025, the filing deadline is April 15, 2026. Because the mirror system adopts federal procedural rules, the same extension options available to mainland filers generally apply to Guam returns.

Self-employed bona fide Guam residents who owe Form 1040-SS to the IRS get an automatic extension to June 15 without a separate extension form; a statement confirming territorial residency is enough.⁹ The mirror system also inherits federal estimated tax rules, so if you expect to owe $1,000 or more in territorial income tax after withholding and credits, make quarterly estimated payments to the Guam Department of Revenue and Taxation to avoid underpayment penalties.

1
Office of the Law Revision Counsel. 48 USC 1421i – Income Tax
2
Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026
3
eCFR. 26 CFR 1.937-1 – Bona Fide Residency in a Possession
4
Internal Revenue Service. Publication 570 – Tax Guide for Individuals With Income From US Possessions
5
Internal Revenue Service. 2025 Instructions for Form 1040-SS
6
Internal Revenue Service. Instructions for Form 1040-SS (2025)
7
eCFR. 26 CFR 1.935-1 – Coordination of Individual Income Taxes With Guam and the Northern Mariana Islands
8
Internal Revenue Service. Instructions for Form 8898
9
Internal Revenue Service. Instructions for Form 1040-SS (2025)a>