What Is Form W-7 and Why Do Expat Families Need It?

Form W-7 is the IRS application for an Individual Taxpayer Identification Number (ITIN). You need it when someone on your U.S. tax return, typically a non-citizen spouse or foreign-born child, does not have and cannot get a Social Security number. Without an ITIN, the IRS will not process your return, and you cannot claim tax benefits like the standard deduction for married filing jointly or the Credit for Other Dependents.

According to the IRS, Form W-7 must be attached to the federal tax return for which the ITIN is needed. The form cannot be e-filed. It must be mailed or submitted through an IRS-authorized Certifying Acceptance Agent (CAA).

The most common situations that trigger a Form W-7 for expat families are:

Filing jointly with a non-citizen spouse who has no SSN
Claiming foreign-born children as dependents on your return
A nonresident alien with U.S.-source income who needs to file a return or claim treaty benefits

Do You Need an ITIN for Your Spouse or Child?

We’ll confirm whether Form W-7 is required and make sure you apply correctly the first time.

Here is what Form W-7 requires, why the process is harder than it looks, and how Greenback handles it so you do not have to.

Who Needs to File Form W-7?

If your spouse or dependent does not have a Social Security number and you need to include them on your U.S. tax return, they will need an ITIN. The IRS requires an ITIN for anyone listed on a return who claims an allowable tax benefit but is not eligible for an SSN.

For a full breakdown of who qualifies and the specific scenarios that trigger ITIN requirements, see our detailed guide: Do I Need an ITIN and How Do I Obtain One?

Why Does Form W-7 Matter So Much for Expat Families?

For most American expats, Form W-7 is not about their own tax filing. It is about unlocking tax benefits that depend on including family members on the return. The financial impact is significant.

Filing Jointly with a Non-Citizen Spouse

Without your spouse’s ITIN, you cannot file a joint return. That means you lose access to the $31,500 standard deduction for married filing jointly (2026 tax year). Filing separately with a non-resident alien spouse drops your standard deduction to $15,750, and you may lose eligibility for certain credits entirely.

Example: James earns $95,000 teaching at an international school in Thailand. His Thai wife has no income. If he files jointly with her ITIN, he claims the full $130,000 Foreign Earned Income Exclusion and the $31,500 standard deduction. His U.S. tax bill: $0. If he files separately without her ITIN, his deduction drops by nearly $16,000, and his tax situation becomes more complicated.

For a deeper look at how joint filing with a non-citizen spouse works, see our guide: Filing Joint Taxes with a Foreign Spouse.

Claiming Foreign-Born Children

Children with ITINs cannot be claimed for the Child Tax Credit (which requires an SSN). However, they do qualify for the $500 Credit for Other Dependents. For families with multiple children, this adds up quickly, but only if each child has a valid ITIN.

If you are starting the SSN application process for your child at a U.S. embassy or consulate, an ITIN can serve as a bridge to keep you compliant and to claim available credits while you wait.

Claiming Treaty Benefits

Nonresident aliens who receive U.S.-source income, such as dividends, interest, royalties, or compensation, may need an ITIN to claim reduced withholding rates under a U.S. tax treaty. The ITIN must be obtained before the treaty benefit can be applied.

What Makes Form W-7 Difficult for Expats?

Form W-7 looks simple. It is two pages. But for Americans living abroad, the application process creates problems that are not obvious until you are already in the middle of it.

You Cannot E-File

Any tax return that includes a new Form W-7 must be paper-filed. For expats who are used to filing electronically, this means printing, mailing internationally, and waiting significantly longer for processing. Your return will not be processed until the IRS issues the ITIN, which adds 7 to 11 weeks to your timeline.

Your Passport Disappears for Months

If you mail Form W-7 directly to the IRS, you must include original identity documents or certified copies from the issuing agency. Most applicants use a passport. That means mailing your original passport (or your spouse’s or child’s passport) to Austin, Texas, and waiting up to 60 days to get it back. For expats who need their passports for daily life, work, banking, or travel, this is a serious problem.

Document Requirements Are Strict

The IRS accepts 13 types of identity documents, but most applicants rely on a passport because it satisfies both the identity and foreign status requirements in a single document. If you use alternative documents (such as a national ID card and a birth certificate), both must be originals or certified copies issued by the issuing agency. Notarized copies are not accepted. For dependents under age 6, the IRS accepts medical records. For dependents under 24, school records may also work, but they must be originals.

Mistakes Cause Rejections and Start the Process Over

If the IRS rejects your Form W-7 (notice CP567), your documents are returned within 60 days, but you must correct the errors and resubmit from scratch. Processing time starts over. Common rejection reasons include incomplete information, insufficient documentation, and failing to attach the correct tax return. For families applying for multiple ITINs, a single error on one form can delay the entire filing.

Timing Matters More Than You Think

The IRS processes ITIN applications more quickly outside tax season. During peak periods (January 15 through April 30), processing times stretch from 7 weeks to 9 to 11 weeks. If you submit during peak season from overseas, you should expect the longer end of that range. Starting the process early, ideally three months before any filing deadline, can make a meaningful difference.

Stop Guessing About ITIN Rules

We’ll walk you through Form W-7 step by step and ensure your return is filed correctly.

How Greenback Eliminates These Problems

Greenback is an IRS-authorized Certifying Acceptance Agent (CAA). This is a specific IRS designation that allows us to verify your identity documents in-house and submit your Form W-7 application on your behalf. Here is why that matters.

Your Passport Stays with You

As a CAA, Greenback reviews and authenticates your passport (and other documents) directly. We verify them, attach a Certificate of Accuracy (Form W-7 COA) to your application, and submit it to the IRS. Your original documents are returned to you immediately, not mailed to Austin for months.

We Handle the Paperwork End to End

Your Greenback accountant prepares your Form W-7, reviews all supporting documentation, coordinates the ITIN application with your tax return filing, and submits the complete package to the IRS. You do not need to figure out which documents qualify, how to get certified copies, or where to mail anything.

Applications Are Accepted on the First Submission

Because Greenback’s CPAs and Enrolled Agents prepare and review every Form W-7 before submission, errors that cause IRS rejections are caught before they happen. That means no CP567 rejection notices, no resubmissions, and no extra months of waiting.

Family Applications Are Coordinated

If you need ITINs for your spouse and multiple children, each person requires a separate Form W-7 attached to the same tax return. Greenback coordinates all applications, ensuring consistent documentation and reducing per-person costs. For pricing details, see our additional services page or read our guide on how much an ITIN costs.

What About ITIN Renewals?

ITINs expire if they are not used on a federal tax return for three consecutive years. If your ITIN (or your spouse’s or child’s ITIN) has expired, you will need to renew it using the same Form W-7 process before the IRS will process a return that includes it.

The renewal process follows the same rules as a first-time application: the same documents, the same processing time, and the same requirement to paper-file. Greenback handles renewals using the same CAA document authentication, avoiding the mailing of original passports.

To check whether your family’s ITINs are still valid, see our guide: Is My ITIN Expired? How to Check and What to Do Next.

What Should I Do Next?

If you need an ITIN for your spouse, children, or yourself, the smartest move is to start early and work with a Certifying Acceptance Agent. The process takes 7 to 11 weeks, even when everything goes smoothly, and delays from document issues or peak-season backlogs can stretch that further.

No matter how late, messy, or complex your return may be, we can help. You will have peace of mind, knowing that your taxes were done right and your family’s ITIN applications were handled by professionals who do this every day.

If you are married to a non-U.S. citizen and need guidance on how ITIN filing fits with your overall tax strategy, learn more about how we help expats filing with a foreign spouse.

If you are ready to be matched with a Greenback accountant, click the get started button below. For general questions about the ITIN process or working with Greenback, contact us, and one of our Customer Champions will be happy to help.

Get Your ITIN Right the First Time

We’ll prepare your Form W-7, coordinate it with your tax return, and help you avoid delays or rejected filings.

This article is for informational purposes only and does not constitute tax, legal, or accounting advice. Every expat family’s situation is unique. For guidance specific to your ITIN application and tax return, contact Greenback to speak with an expat tax specialist.