ITIN for Your Foreign Spouse: Filing Jointly Under Section 6013(g) — A US Tax Year-One Playbook

Marrying someone who lives outside the United States changes your next US tax return more than most couples expect. The choice between filing separately and filing jointly is not really about preference — it is about a one-time tax election that has multi-year consequences, runs through a specific IRS code section, and requires the spouse to be identified with an ITIN.

This guide walks through how to decide whether joint filing actually saves you money, how Section 6013(g) works, the specific W-7 reason code for spouses, and the situations we see going wrong every March and April when couples try to put this together themselves.

When filing jointly actually saves you money

The default for a US citizen or resident married to a non-resident alien is Married Filing Separately (MFS). You file your own return, your spouse is not on it, and your spouse's foreign income is invisible to the IRS. Simple — but it is rarely the cheapest option.

The other choice is Married Filing Jointly (MFJ), which requires your foreign spouse to be treated as a US resident for tax purposes for the year. That treatment is what unlocks the larger standard deduction, the wider tax brackets, and several credits that MFS excludes or phases out faster.

The standard deduction comparison alone is striking. For 2026:

• MFJ standard deduction: roughly US$30,000
• MFS standard deduction: roughly US$15,000

For a US citizen earning, say, US$120,000 with a non-resident spouse who has no income, MFJ typically saves several thousand dollars in federal tax versus MFS. State tax often follows the federal status, so the saving can be larger in high-tax states.

Where MFJ stops being obvious is when your spouse earns significant income in their home country. Joint filing brings that income onto the US return — but a Foreign Tax Credit or the Foreign Earned Income Exclusion usually offsets the US tax on it. The math is case-specific. Before we tell anyone to elect MFJ, we run the actual numbers both ways using the spouse's foreign income, foreign tax paid, and any treaty positions.

Section 6013(g): the election that unlocks joint filing

The Internal Revenue Code does not automatically let a US citizen file jointly with a non-resident spouse. By default, the non-resident spouse is a "non-resident alien" (NRA) and cannot be a party to a joint return.

Section 6013(g) is the workaround. It is the part of the tax code that lets the two spouses jointly elect to treat the NRA spouse as a US resident for the entire tax year. Once the election is in place:

• The NRA spouse is treated as a US resident for income-tax purposes only (not for immigration, not for FBAR, not for any other federal regime).
• Both spouses' worldwide income for the year is reported on the joint return.
• The couple files Form 1040 as MFJ instead of separate returns.

The election is made by attaching a signed statement to the first joint return. The IRS does not have a form for this — you write it. A correctly worded statement contains:

• A declaration that one spouse is a US citizen or resident and the other is a non-resident alien at year-end.
• An election under Section 6013(g) to treat the non-resident as a resident for the tax year.
• Both spouses' names, addresses, and tax IDs (SSN for the US spouse, ITIN for the non-resident).
• Both spouses' signatures.

A standard-format election statement is part of every spouse-ITIN package we prepare.

The trade-off: worldwide income becomes US-taxable

The trade you make in exchange for MFJ is that your spouse's foreign-source income joins your return. This is where many couples first hear about the Foreign Earned Income Exclusion (FEIE, Form 2555) and the Foreign Tax Credit (FTC, Form 1116).

• FEIE lets a US-resident taxpayer exclude up to ~US$130,000 (2026, indexed annually) of foreign earned income from US tax. It requires either the bona fide residence test or the physical presence test (330 days abroad in any 12 consecutive months).
• FTC lets you claim a dollar-for-dollar credit against US tax for income tax already paid to your spouse's home country. It is more flexible than FEIE and works for non-earned income (pensions, investments) too.

For most jointly-filing couples we work with, the FEIE or FTC eliminates the additional US tax on the foreign spouse's home-country income — so the MFJ election delivers the standard-deduction and bracket-widening benefits without creating a US tax bill on the foreign income.

Edge cases where it gets harder: foreign rental income that does not qualify for FEIE; foreign pension income that has complex US character; foreign-LLC participation where Subpart F or PFIC rules can attach. We screen for these before recommending MFJ.

Section 6013(g) is a one-way door once revoked

The election runs forward indefinitely once made. It applies to every joint return after the first one — no need to re-elect annually. It can be revoked, but revocation is permanent:

"Once a Section 6013(g) election has been revoked, the same individuals cannot re-elect it for any future year."

This is why the first joint return is more consequential than couples realise. If you revoke after three years because your circumstances changed, you cannot un-revoke in year six.

In practice, the situations where we recommend revocation are narrow: the spouse moves back permanently and acquires US residency through other means (green card), or the spouse's foreign income grows to a level where the FEIE/FTC offset breaks down. Most couples stay in MFJ for the life of the marriage.

The W-7 reason code for spouses

For a Form W-7 ITIN application by a non-resident spouse filing jointly, the relevant reason code is:

• (e) — Spouse of US citizen/resident alien. Used when the spouse is electing to file MFJ with their US citizen or resident partner.

If the spouse is also a dependent of someone else (rare), reason (d) applies instead. For most cases (e) is the correct code.

The supporting evidence the IRS expects:

• A valid, unexpired passport for the spouse — verified online by our CAA so the original stays with you.
• The marriage certificate, with certified English translation if not originally in English.
• The Section 6013(g) election statement, signed by both spouses.
• The Form 1040 itself, with both names and the spouse's ITIN field marked "applied for" pending issuance.

The IRS scrutinises the marriage certificate closely. Common-law marriages, customary marriages, and marriages registered in jurisdictions that do not issue centralised certificates require additional documentation — typically an affidavit and a translated statement from the issuing authority. We handle these on case-by-case basis.

The right sequence: W-7 and 1040 together, not apart

The IRS expects the W-7 and the related 1040 to be submitted as one package. Filing the 1040 first and the W-7 separately later is the single most common reason couples find themselves in a frustrating loop: the return cannot be processed without the ITIN, and the ITIN application is treated as standalone, which slows everything down.

The clean sequence:

1. Confirm joint filing is the right call — we run MFJ vs MFS for your specific numbers.
2. Prepare the 1040 with both names, both signatures, and a clearly indicated "applied for" status in the spouse's tax-ID field.
3. Prepare the W-7 with reason (e) and the spouse's identifying details exactly matching the passport.
4. Draft the Section 6013(g) election statement for both signatures.
5. Schedule CAA online passport verification — a video call where we verify the spouse's passport on the IRS's behalf.
6. Translate the marriage certificate and any non-English supporting documents.
7. Mail the full package (W-7 + 1040 + election statement + certified passport copy + marriage certificate) to the IRS ITIN Operation in Austin, Texas, via tracked delivery.
8. Track until ITIN is issued (typically 7–11 weeks; up to 14 weeks during the January–April peak).
9. Return processing continues automatically once the ITIN is assigned — no separate filing is needed.

We routinely run this whole sequence in roughly 7–10 business days of preparation under the Standard package, or 1–3 business days under Priority. IRS processing time is what it is.

Children: when their ITINs make sense after TCJA

Many couples ask about applying for ITINs for non-resident children at the same time as the spouse. Pre-2018 this was almost always worth doing because of the Child Tax Credit. After the Tax Cuts and Jobs Act (TCJA), the rules changed:

• The Child Tax Credit (up to US$2,000 per qualifying child) now requires the child to have an SSN, not an ITIN.
• The Credit for Other Dependents ($500 per dependent) does work for dependents with ITINs, but it requires the dependent to be a qualifying relative with a US-source nexus or to live in the US, Canada, or Mexico.
• For dependents living elsewhere with no US presence, the practical benefit of obtaining an ITIN is often zero in any given tax year.

So our recommendation depends on the actual numbers:

• Child has US-source income (rare but happens — US-issued royalties, US trust distributions, US scholarship) → ITIN is needed for the child's own filing requirement.
• Child is filing a US return alongside the parents → ITIN required.
• Child is just listed on the parents' joint return as a dependent who lives abroad → in most cases ITIN gives no tax savings, and we say so.

For families where the math works (typically those with the child living in the US for part of the year, or with US-source income to report), we package the children's W-7s with reason (d) — Dependent of US citizen/resident alien — alongside the spouse's W-7 with reason (e). The 20% second-applicant discount applies to family packages.

Amending a past return: the 1040-X path

A common situation: a US citizen or green-card holder filed solo for one or two prior years before realising the joint-filing route existed. The IRS does not forbid this — you can fix it with Form 1040-X, the amended return.

The window: three years from the original return's due date (or two years from when the tax was paid, whichever is later) to file the amendment. For 2024 returns originally due 15 April 2025, the deadline to amend is 15 April 2028.

The 1040-X package looks almost identical to the original-return package above, with two additions:

• Form 1040-X itself, showing the changes from MFS (or single) to MFJ and the resulting tax difference.
• A brief explanation in Part III of the 1040-X stating that the change is to add a foreign spouse under Section 6013(g).

If the amendment generates a refund, the IRS typically pays it 12–16 weeks after accepting the amendment. If it generates additional tax owed, that tax is due with the amendment.

Common reasons applications get rejected

From the cases we see come in already-rejected:

• Passport quality issues. The IRS rejects W-7 packages with passport copies that are blurry, cropped, missing pages, or photocopied from a CAA whose authorisation is not in good standing. Online CAA verification with a real-time video call produces a higher-quality record than a notarised photocopy.
• Marriage certificate not translated. Non-English marriage certificates need certified English translation. A self-translation is not certified.
• Section 6013(g) statement missing. Some couples remember the W-7 but forget the election statement, or write a statement that does not include the IRC reference and both signatures.
• Inconsistent name spelling. The spouse's name on the W-7 must match the passport's machine-readable zone (MRZ) exactly — including transliterated form for non-Latin scripts. Mismatches with how the spouse normally signs day-to-day cause rejections.
• Filing W-7 without an attached return. Reason (e) requires the W-7 to be filed with the related 1040 (or 1040-X) unless a narrow exception applies.

We see roughly one re-do case per month — most are passport-related from couples who used a notarised photocopy through a local agent instead of a CAA. The re-do is straightforward; the wasted 3–4 months waiting for the first rejection is not.

Edge cases we handle regularly

• Active-duty military and DoD-contractor families. Stationed overseas, foreign spouse, mixed-currency pay. Fully remote process works.
• Adjustment-of-status couples. Spouse currently in the US on a non-immigrant visa with a pending I-485. Still requires an ITIN until the SSN is issued post-adjustment.
• Couples in treaty countries with significant foreign income. FEIE vs FTC modelling is part of the engagement.
• Common-law and customary marriages. Documented through home-country statutes plus an affidavit. We coordinate with local counsel where needed.
• Spouse with expired passport. Renewal of the passport happens at the spouse's home-country embassy or consulate before W-7. We sequence the work.

Frequently asked questions

The FAQ block above answers the most common questions we receive every spring. If your case has more than one moving part — overseas military assignment plus children plus a past unamended year, for example — book an eligibility review and we will map the full picture before you spend on any service.