Marrying a non-U.S. citizen: tax implications

You're a U.S. citizen abroad. You marry someone who is not a U.S. person — a foreign citizen with no U.S. tax connection. Your U.S. tax life just got more complicated, even though they are not (yet) a U.S. taxpayer.

The good news: with careful planning, marriage to a non-U.S. spouse can leave you better off than marriage to another U.S. person. The bad news: do nothing and your filing status defaults to a punitive one, your FBAR/FATCA exposure may grow without you noticing, and the unlimited spousal gift-tax exemption that protects most U.S. couples doesn't apply to you.

This article covers the practical tax decisions in the months around the marriage.

The two filing options

When you marry a non-U.S. person, you have two filing-status options on your U.S. tax return:

Option 1: Married Filing Separately (MFS) — default

If you do nothing, the IRS treats you as Married Filing Separately. Your foreign-citizen spouse is a "nonresident alien" and is not part of your U.S. tax return at all. Their worldwide income stays out of the U.S. tax system.

This sounds appealing — your spouse stays invisible — but MFS has costs:

• Filing threshold collapses. Single filers must file if income > $14,600; MFS filers must file if income > $5. The latter is essentially zero. Almost any U.S. tax obligation reaches you.
• Worse tax brackets. MFS brackets are narrower than Single brackets. You pay more on the same income.
• Disabled credits. The Earned Income Tax Credit is fully off-limits. The Child Tax Credit is technically available but with stricter limits.
• Loss of education credits. American Opportunity Credit and Lifetime Learning Credit are unavailable to MFS filers.
• Roth IRA phase-out crashes. The MFS phase-out is $0–$10,000 — essentially zero contribution unless your income is very low. See Roth IRA while abroad.
• Capital loss limit halved. $1,500/year instead of $3,000/year.

Option 2: Elect to treat your spouse as a U.S. resident — file Married Filing Jointly (MFJ)

You can elect, under IRC §6013(g), to treat your non-U.S. spouse as a U.S. tax resident for the year. You then file Married Filing Jointly. The upside:

• Full MFJ tax brackets — much wider than MFS.
• Full standard deduction ($29,200 for 2025) instead of the $14,600 MFS gets.
• Full Roth IRA contribution thresholds.
• Refundable Child Tax Credit available for U.S.-citizen kids.
• All education credits available.
• $3,000/year capital loss deduction.

The catch: your foreign spouse's worldwide income becomes part of your joint return. If your spouse has substantial foreign earnings, this can push your joint taxable income higher than your MFS taxable income alone — possibly enough to offset the MFJ benefits.

The decision is a math problem. For most expat couples where the foreign spouse has modest local earnings (and you can use FEIE or FTC to shelter the income), MFJ wins. For couples where the foreign spouse has very high foreign income (a foreign business owner, a senior executive of a foreign company, etc.), MFS can be cheaper.

The §6013(g) election mechanics

Making the MFJ election:

1. Get your spouse an ITIN. Your spouse needs a U.S. taxpayer identification number. File Form W-7 with the first joint return. See ITIN vs. SSN.
2. Attach a written election statement to the first joint return. The statement says you both elect under §6013(g) to treat the foreign spouse as a U.S. resident for the year and all subsequent years.
3. Both sign the return. Both spouses' signatures are required on MFJ returns.

The election, once made, continues automatically every year. Either spouse can revoke in a subsequent year (effectively going back to MFS) — but once revoked, you can never re-elect §6013(g) treatment for that marriage. A one-time-only switch.

The FBAR / FATCA expansion problem

Marriage doesn't change your own FBAR obligations — your accounts are still your accounts. But it can dramatically expand them:

• Signature authority over your spouse's accounts triggers FBAR reporting (even without a financial interest). If you become a co-signer on your spouse's local checking account in Tokyo, you owe FBAR on it. See what is FBAR.
• Joint accounts opened during the marriage are reportable.
• Form 8938 thresholds reflect your assets. Joint ownership is generally aggregated for the financial-interest test. See what is FATCA.

If you file MFJ and your spouse becomes a U.S. tax resident under §6013(g), all of their accounts also become FBAR-reportable in their own name. The information-return burden roughly doubles.

This is the most underappreciated cost of MFJ: filing one joint return doesn't just affect income tax — it pulls your spouse's entire financial life into U.S. reporting.

The disappearing spousal gift-tax exemption

For two U.S. citizens, lifetime gifts between spouses are unlimited and untaxed. You can transfer your entire net worth to your U.S.-citizen spouse with no gift tax.

For a U.S. citizen married to a non-U.S.-citizen spouse, the unlimited spousal exemption disappears. Instead, you have an annual cap — $190,000 for 2025 (adjusted annually for inflation).

Gifts above the annual cap to a non-citizen spouse:

• Are reportable on Form 709
• Eat into your lifetime gift/estate exemption (~$13.99M in 2025, scheduled to drop after 2025)
• Eventually become taxable when the lifetime exemption is exhausted

This is the rule that catches expats moving abroad with substantial wealth. A spouse-to-spouse property transfer that would be tax-free in the U.S. context can produce a Form 709 filing requirement when one spouse is foreign.

The fix is usually to structure transfers below the annual cap each year rather than transferring all at once, or to keep separate ownership where possible.

Spousal estate planning

The estate-tax angle mirrors the gift-tax angle:

• A U.S. citizen's estate can pass unlimited to a U.S.-citizen surviving spouse free of federal estate tax.
• A U.S. citizen's estate passing to a non-U.S.-citizen surviving spouse loses the unlimited marital deduction. The estate is taxed above the $13.99M lifetime exemption (less if depleted by prior gifts).

The standard fix is a Qualified Domestic Trust (QDOT) — assets pass into a trust at death rather than directly to the foreign spouse. The trust preserves the marital deduction provided certain U.S. trustee and reporting requirements are met. Setting this up is estate-planning attorney territory; if you have meaningful assets and a non-U.S. spouse, it's worth the consult.

Filing status with kids

If you have U.S.-citizen children together (kids born to a U.S.-citizen parent abroad — see kids born abroad):

• Under MFS: you can claim the U.S.-citizen kids as dependents on your individual return. The Child Tax Credit is available; the refundable portion (ACTC) is reduced for MFS.
• Under MFJ: full CTC + ACTC available, often making MFJ noticeably better with kids.

For mixed-status families with U.S. citizen kids, MFJ is almost always the right answer purely on the CTC math. See Child Tax Credit from abroad.

Practical pre- and post-marriage planning

Before the wedding (if you have time)

• Audit your accounts. If you'll add your spouse as a co-signer to your existing accounts, plan to file FBAR for those accounts going forward.
• Estate planning. If you have significant assets, consult a cross-border estate attorney about a QDOT or alternative structures.
• Consider a prenup. Beyond divorce protection, a prenup can clarify separate vs. joint property — useful for both U.S. tax purposes and foreign-country family law.

The first joint tax year

• Decide MFJ vs. MFS. Run the math both ways. For most expat couples in the U.S. expat-tax client base, MFJ + FEIE/FTC nets cheaper.
• Get your spouse an ITIN if filing MFJ. Allow 7–11 weeks for processing. See ITIN vs. SSN.
• File the §6013(g) statement with the first joint return.
• File FBAR / 8938 for any new joint accounts that crossed the thresholds.

Ongoing

• Update FBAR each year for newly added joint accounts.
• Track lifetime gifts to your foreign spouse — every year above the annual cap chips into your lifetime exemption.
• Reassess MFJ vs. MFS if your spouse's income changes materially. Once a year is fine.

Common marriage-to-foreigner mistakes

• Defaulting to MFS without doing the math. Often costs $3,000–$10,000/year in unnecessary U.S. tax.
• Filing MFJ but forgetting to file the §6013(g) election statement. Technically invalid.
• Adding the foreign spouse to a U.S. financial account without re-running the W-9 / W-8 paperwork. Causes ugly back-and-forth with the broker.
• Gifting large amounts to a non-citizen spouse without realizing the $190K cap. Triggers Form 709.
• Forgetting to file FBAR when becoming a co-signer on the spouse's foreign accounts.
• Skipping cross-border estate planning because "we're young." The marital deduction matters even at modest asset levels for cross-border couples.

Next steps

• ITIN vs. SSN — for the W-7 process
• Child Tax Credit from abroad
• FEIE vs. Foreign Tax Credit
• Kids born abroad: citizenship and tax