How to File Taxes When Your Spouse Is Not a US Citizen

Filing taxes when your spouse is not a U.S. citizen starts with one question: does the IRS consider your spouse a resident alien or a nonresident alien? That classification decides whether you can file jointly, what income you have to report, and which credits and deductions are on the table. For the 2026 tax year, filing jointly gives you a $32,200 standard deduction against $16,100 for married filing separately, so the answer matters in real dollars.¹

Is Your Spouse a Resident or Nonresident Alien

A resident alien is taxed like a U.S. citizen: worldwide income from every source goes on Form 1040.² A nonresident alien generally owes U.S. tax only on U.S.-source income.³

Under 26 U.S.C. § 7701(b), your spouse is a resident alien if either of two tests is met.⁴ The green card test: holding lawful permanent resident status at any point during the calendar year makes your spouse a resident alien for that entire year. The substantial presence test: your spouse was in the U.S. at least 31 days during the current year, and the weighted total across three years reaches 183. The formula counts every day in the current year at full value, one-third of each day in the prior year, and one-sixth of each day the year before that.⁵

Some days don’t count. F and J student visa days, foreign government diplomat days, and a few other exempt categories drop out of the calculation.⁴ A closer connection exception is also available: if your spouse was present fewer than 183 days in the current year and can show a tax home in a foreign country with stronger ties than to the U.S., they can stay a nonresident even when the weighted formula hits 183.

If your spouse becomes a resident partway through the year (a July green card, for example), they are a dual-status alien for that tax year. Only U.S.-source income is taxed for the nonresident portion; worldwide income is taxed for the resident portion.⁶ Most couples in this situation skip dual-status filing by making the joint election described next, which treats the spouse as a resident for the full year.

Electing to File Jointly Under Section 6013(g)

Joint filing is normally off-limits when one spouse is a nonresident alien. Internal Revenue Code Section 6013(g) creates the exception: the U.S. citizen or resident spouse can elect to treat the nonresident spouse as a resident alien for the whole year, which opens up Married Filing Jointly.⁷

How to Make the Election

Both spouses attach a signed statement to the joint Form 1040 for the first year the election takes effect. The statement needs both names, addresses, and Social Security numbers or ITINs, a declaration that the nonresident spouse agrees to be treated as a U.S. resident for all federal income tax purposes, and both signatures.

Make the election by the return due date for that first year, including extensions. If you miss the deadline, a late election is possible on a showing of reasonable cause and good faith. If you didn’t elect in the first year you could have, you can still elect in a later year and file amended returns on Form 1040-X for earlier open years.⁸

What You’re Signing Up For

Once your spouse is treated as a resident alien, their worldwide income from every country goes on your joint return alongside yours.⁹ If your spouse earns significant income abroad, the additional U.S. tax could offset the benefit of joint rates. Run the numbers before committing.

Your spouse also becomes a U.S. person for foreign account reporting. When the combined value of foreign accounts exceeds $10,000 at any point during the year, your spouse must file FinCEN Form 114, the FBAR.¹⁰ Penalties are steep: up to $10,000 per violation for non-willful failures, and up to the greater of $100,000 or 50% of the account balance for willful ones. Ordinary bank accounts back home count, and this obligation catches many couples off guard.

The One-Election Rule

The election stays in effect year after year until something ends it. Revocation by either spouse ends it. Legal separation, divorce, or the death of either spouse ends it. The IRS can also terminate it if your spouse won’t keep adequate records or cooperate with information requests.

Once terminated for any reason, the same two individuals can never make a 6013(g) election again. If you revoke and later change your mind, you’re permanently barred. Think hard before revoking.

Treaty Tie-Breaker Positions

If your spouse comes from a country with a U.S. income tax treaty, some treaties contain tie-breaker rules that let an individual claim nonresident status for treaty purposes even after a 6013(g) election. Claiming a treaty-based position requires attaching Form 8833 to the return.¹¹ Skipping the form can trigger a $1,000 penalty.¹² Note that claiming nonresident status through a treaty can disqualify your spouse from certain refundable credits, including the Additional Child Tax Credit, so weigh the treaty benefit against the lost credits.

Filing Separately or as Head of Household

Skip the election, and your default is Married Filing Separately. You file Form 1040 with only your own income, take the $16,100 standard deduction for 2026, and lose access to a number of credits and deductions that joint filers get freely.¹

If your nonresident alien spouse has U.S.-source income, they file their own Form 1040-NR.³ Income effectively connected with a U.S. trade or business is taxed at graduated rates. Other U.S.-source income like dividends, rents, and royalties is generally subject to a flat 30% withholding, unless a treaty lowers the rate.¹³

Head of Household as a Better Option

Head of Household is often a significant upgrade over MFS. The 2026 standard deduction is $24,150, and the brackets are wider.¹ The IRS treats you as unmarried for this purpose if your spouse was a nonresident alien at any time during the year and you did not elect to treat them as a resident.¹⁴

Your nonresident spouse cannot be the qualifying person. You need someone else, typically a dependent child who lives with you more than half the year, and you must pay more than half the cost of maintaining the household.¹⁴ No qualifying person, no HOH.

Community Property States

Filing separately gets complicated in a community property state. Nine states apply community property rules: Arizona, California, Idaho, Louisiana, Nevada, New Mexico, Texas, Washington, and Wisconsin.¹⁵ Income either spouse earns during the marriage is treated as jointly owned, so filing MFS usually means each of you reports half of the combined community income, even if only one of you earned it.

Section 66 of the Internal Revenue Code creates a narrow exception for spouses who live apart the entire calendar year, don’t file jointly, and don’t transfer earned income between themselves before year-end.¹⁶ Meet all the conditions and each spouse reports only their own earned income. Couples still living together in these states generally have to split community income on both returns.

Getting an ITIN for Your Spouse

A spouse without a Social Security number needs an Individual Taxpayer Identification Number to appear on a joint return or for you to claim certain credits. Apply on Form W-7.¹⁷

The W-7 asks for the reason the ITIN is needed (electing to file a joint return, in this case) and must be submitted with identity documents proving both identity and foreign status. A passport is the strongest single document because it satisfies both requirements on its own. Without a passport, you’ll need at least two other documents with a photograph. The IRS accepts originals or certified copies from the issuing agency. Notarized photocopies are not accepted.

Three submission routes exist:

Mail the completed W-7, the tax return, and the required identity documents to the IRS ITIN Operation office in Austin, Texas. Slowest option, and it puts an original passport in the mail.
Use a Certifying Acceptance Agent. A CAA is authorized by the IRS to review original documents in person and certify copies. Your spouse keeps the documents. Private CAA fees vary.
Visit an IRS Taxpayer Assistance Center by appointment. Staff verify originals in person and forward certified copies. Appointments can be hard to secure during filing season.

The W-7 must accompany the tax return it’s for. The IRS won’t process a standalone W-7 tied to a spouse election. On the return, enter your spouse’s name and write “ITIN APPLIED FOR” in the SSN field.

ITINs expire if they aren’t used on a federal tax return for three consecutive years, with expiration falling on December 31 following that third year of non-use.¹⁸ Renewal uses the same Form W-7.

Handling Foreign Income Without Getting Taxed Twice

Once your spouse elects resident status and reports worldwide income, you risk paying U.S. tax on money already taxed by a foreign government. Two tools exist, and the right one depends on the type of income.

Foreign Tax Credit

The Foreign Tax Credit offsets your U.S. tax dollar-for-dollar against income taxes your spouse already paid to another country. Claim it on Form 1116.¹⁹ It applies to income taxes, war profits taxes, and excess profits taxes paid to a foreign government, and it covers all types of foreign income: wages, investment income, business profits.

The credit can’t exceed the U.S. tax attributable to the foreign income, so if the foreign rate is higher, you’ll have leftover credit. Excess credits carry forward up to ten years.¹⁹ For most couples, the credit is the more flexible option because it covers all income types and doesn’t require living abroad.

Foreign Earned Income Exclusion

The Foreign Earned Income Exclusion lets your spouse exclude up to $132,900 of foreign wages and self-employment income from U.S. tax for the 2026 tax year.²⁰ To qualify, your spouse needs a tax home in a foreign country and must either be a bona fide resident of that country for an entire tax year or be physically present abroad at least 330 days in a 12-month period. The exclusion applies only to earned income. Investment income, pensions, and government pay don’t qualify.

You can’t use the exclusion and the credit on the same income. Excluding $132,900 of foreign wages means no credit is available on the foreign taxes paid on that excluded income.¹⁹ Many couples pair the exclusion for earned income with the credit for whatever isn’t excluded, but the numbers deserve a side-by-side check before you file.

How to Send the Return and What to Expect

A return filed with the 6013(g) election or a W-7 attached generally can’t be e-filed. The election statement and the identity documents require manual handling. Assemble a physical package:

The completed and signed Form 1040
The signed Section 6013(g) election statement
Form W-7 with identity documents, if applying for an ITIN
Form 8833, if taking a treaty-based position

The whole package goes to the IRS ITIN Operation office in Austin, Texas, so the W-7 and the return are processed together. A missing document restarts the process, so double-check before mailing.

Returns filed with a W-7 take about seven weeks to process under normal conditions, and nine to eleven weeks during peak filing season (January 15 through April 30) or from overseas.²¹ Refunds don’t go out until the ITIN is assigned and the full return is processed. Filing early, before the peak window, can save weeks.

A Note on Gifts and Estates

Filing status is only part of the picture for mixed-citizenship couples. The unlimited marital deduction that lets citizen spouses leave everything to each other tax-free doesn’t apply when the surviving spouse is not a U.S. citizen. Lifetime gifts to a non-citizen spouse are capped at $194,000 per year for 2026 before gift tax applies.¹ To preserve the marital deduction at death, assets must pass through a Qualified Domestic Trust, which requires at least one U.S. citizen or domestic corporation as trustee and specific withholding provisions.²² The 2026 federal estate tax exemption is $15,000,000 per person, so estates below that owe no federal estate tax regardless of citizenship, but larger estates need a QDOT established before the estate tax return deadline to defer the tax. These are separate returns handled outside your annual 1040, but knowing they exist is worth the mention before you make gifts or estate plans on autopilot.

1
Internal Revenue Service. Rev. Proc. 2025-32
2
Internal Revenue Service. Reporting Foreign Income and Filing a Tax Return When Living Abroad
3
Internal Revenue Service. Taxation of Nonresident Aliens
4
Office of the Law Revision Counsel. 26 U.S. Code 7701 – Definitions
5
Internal Revenue Service. Substantial Presence Test
6
Internal Revenue Service. Taxation of Dual-Status Individuals
7
Office of the Law Revision Counsel. 26 USC 6013 – Joint Returns of Income Tax by Husband and Wife
8
Internal Revenue Service. Instructions for Form 1040-X
9
Internal Revenue Service. Foreign Earned Income Exclusion
10
Internal Revenue Service. Report of Foreign Bank and Financial Accounts (FBAR)
11
Internal Revenue Service. About Form 8833, Treaty-Based Return Position Disclosure Under Section 6114 or 7701(b)
12
Internal Revenue Service. Form 8833 – Treaty-Based Return Position Disclosure Under Section 6114 or 7701(b)
13
Internal Revenue Service. Fixed, Determinable, Annual, or Periodical (FDAP) Income
14
Internal Revenue Service. U.S. Citizens and Residents Abroad – Head of Household
15
Internal Revenue Service. Publication 555 (12/2024), Community Property
16
Office of the Law Revision Counsel. 26 U.S. Code 66 – Treatment of Community Income
17
Internal Revenue Service. About Form W-7, Application for IRS Individual Taxpayer Identification Number
18
Internal Revenue Service. How to Renew an ITIN
19
Internal Revenue Service. Foreign Tax Credit
20
Internal Revenue Service. Figuring the Foreign Earned Income Exclusion
21
Internal Revenue Service. Individual Taxpayer Identification Number (ITIN)
22
Office of the Law Revision Counsel. 26 USC 2056A – Qualified Domestic Trust