US citizens living abroad generally need a Social Security number (SSN) to file a US tax return. If you are a US citizen who has never received an SSN, you should apply for one through the Social Security Administration.
An Individual Taxpayer Identification Number (ITIN) is generally not an alternative for US citizens. Eligible non-US citizens who cannot obtain an SSN may use an ITIN instead.
Some Americans have lived overseas their entire lives without ever receiving a US Social Security number.
Others were born in the United States, moved abroad as children, and only discovered their US tax obligations years later.
This creates an important question: How can you file a US tax return if you do not have an SSN?
The answer depends on your citizenship and eligibility for a taxpayer identification number. US citizens generally need an SSN, while certain foreign nationals may qualify for an ITIN. Understanding this distinction is especially important if you have never filed US taxes, need to report foreign income, or want to become compliant with the IRS.
Key Takeaways: Filing US Taxes Without an SSN
SSN requirement: US citizens generally need an SSN to file federal income tax returns.
Living abroad: Living abroad does not remove US tax filing obligations.
Applying from overseas: Americans who have never received an SSN can apply from overseas.
ITIN limits: US citizens generally cannot use an ITIN instead of an SSN.
ITIN eligibility: Eligible non-US citizens may apply for an ITIN using Form W-7.
Nonresident spouses: A nonresident alien spouse does not always need an SSN or ITIN when the American spouse files separately.
Overdue returns: Americans with overdue returns should obtain the correct identification number before using the Streamlined Filing Compliance Procedures.
SSN and ITIN Requirements for US Expats
| Situation | What you generally need |
|---|---|
| US citizen living abroad without an SSN | Apply for an SSN |
| US citizen who lost their Social Security card | Recover the existing number or request a replacement card |
| Dual US citizen who has never lived in America | Apply for an SSN |
| Non-US citizen ineligible for an SSN | May qualify for an ITIN |
| American married to a nonresident alien | Spouse’s ITIN may be needed depending on filing circumstances |
| American with overdue US tax returns | Obtain an SSN before making a Streamlined Filing submission |
| US citizen with no US income | May still have filing obligations based on worldwide income |
Why Do US Expats Need a Social Security Number?
The IRS uses taxpayer identification numbers to process returns, associate income with taxpayers, and maintain tax records.
For US citizens, the appropriate taxpayer identification number is generally an SSN. This requirement applies whether you live in California, Germany, Australia, or another country.
US citizens generally remain subject to US taxation on worldwide income, even when they have lived overseas for many years. For example, an American living in France who earns €70,000 from a French employer may need to file a US federal income tax return despite having no US-source income.
Although exclusions and credits may reduce or eliminate US income tax, they do not remove the need for a valid taxpayer identification number. The same US tax filing requirements generally apply to Americans living abroad, regardless of whether their income comes from US or foreign sources.
What If You Are a US Citizen Who Never Had an SSN?
This situation is more common among Americans who were born overseas or moved abroad at a young age.
For example, someone born in the United States who moved to the United Kingdom as an infant may have grown up using only British identification documents. Similarly, a person born abroad to an American parent may have acquired US citizenship at birth without obtaining an SSN.
In both situations, the individual may be a US citizen even if they have never lived or worked in the United States.
US Citizenship is Separate From Having an SSN
Not having a Social Security number does not automatically mean someone is not a US citizen.
Citizenship is determined under US nationality law, while an SSN is an identification number issued by the Social Security Administration.
If you are a US citizen, you generally need to obtain an SSN rather than applying for an ITIN. This distinction is especially relevant for people sometimes described as accidental Americans, who may discover their US citizenship and associated tax responsibilities later in life.
How to Apply for a Social Security Number From Abroad
US citizens living overseas can apply for an SSN without necessarily traveling to the United States.
The process depends on your country of residence and whether you have previously received a number.
Step 1: Confirm Whether You Already Have an SSN
Before applying for a new number, determine whether one was issued to you previously.
For example, your parents may have requested an SSN shortly after your birth.
If you already have a number, you should generally recover it or request a replacement card rather than apply for a new SSN.
Step 2: Contact the Social Security Administration
The Social Security Administration provides services to Americans living overseas through designated Federal Benefits Units and other international arrangements.
Start with the Social Security Administration’s international services to identify the appropriate office for your country.
The office can explain whether your application must be submitted in person, by mail, or through another approved process.
Step 3: Complete Form SS-5
Form SS-5 is the application used to request a Social Security card.
You will generally need to provide information about your identity, citizenship, and other personal details.
The application is free.
Step 4: Prepare Supporting Documents
Depending on your circumstances, you may need documents establishing:
- US citizenship, such as a US passport or qualifying citizenship documentation.
- Age, usually supported by a birth certificate.
- Identity, supported by acceptable current identification.
- Additional information if you are applying for your first SSN as an adult.
The Social Security Administration may require original documents or copies certified by the issuing agency.
Step 5: Submit the Application and Wait for Your SSN
Follow the instructions provided by the office handling your application.
Processing times vary, particularly when additional citizenship or identity verification is necessary.
Once your SSN is issued, you can use it to prepare your US tax returns.
Need Help Getting Compliant?
Universal Tax Professionals helps Americans abroad sort out SSN issues and file the US returns they need.
Can You Use an ITIN Instead of an SSN?
Generally, no. An Individual Taxpayer Identification Number is issued by the IRS to qualifying individuals who need a US taxpayer identification number but are not eligible for an SSN.
It is primarily used by certain non-US citizens, including resident and nonresident aliens with US tax obligations.
For example, a German citizen who earns US rental income and is not eligible for an SSN may need an ITIN to file a US tax return. However, a US citizen living in Germany who has never received an SSN should generally apply for an SSN instead.
SSN vs. ITIN
| Feature | SSN | ITIN |
|---|---|---|
| Issuing agency | Social Security Administration | IRS |
| Available to US citizens | Yes | Generally no |
| Available to certain non-US citizens | Yes, if eligible | Yes, if ineligible for an SSN |
| Used for federal tax filing | Yes | Yes |
| Application form | SS-5 | W-7 |
| Authorizes employment | Depends on immigration status | No |
| Establishes US citizenship | No | No |
An ITIN is not a substitute for an SSN simply because obtaining an SSN from overseas is inconvenient.
What If Your Non-US Spouse Does Not Have an SSN?
American expats frequently marry individuals who are not US citizens.
Whether the foreign spouse needs a US taxpayer identification number depends on how the couple files.
Married Filing Separately
If you are a US citizen married to a nonresident alien and file separately, your spouse may not need an SSN or ITIN.
When the spouse does not have and is not required to have either number, IRS instructions allow the designation “NRA” in the appropriate spouse identification field.
This does not eliminate the American taxpayer’s own SSN requirement.
Married Filing Jointly
Some couples elect to treat the nonresident alien spouse as a US resident for federal income tax purposes.
When making this election and filing jointly, the foreign spouse generally needs an SSN or ITIN.
The election also generally requires reporting both spouses’ worldwide income.
Can You File Overdue US Tax Returns Without an SSN?
Americans who discover their filing obligations after years abroad may need to submit several overdue tax returns.
However, lacking an SSN can complicate the process.
Streamlined Filing Requires a Valid Taxpayer Identification Number
The Streamlined Filing Compliance Procedures allow eligible taxpayers to correct certain past noncompliance when their failures were non-willful.
For US citizens eligible for an SSN, the IRS generally requires a valid SSN to qualify for these procedures.
Submitting a Streamlined Filing package without the required SSN can jeopardize eligibility for the procedures’ favorable penalty treatment.
Therefore, Americans who have never received an SSN should generally obtain one before submitting their Streamlined Filing package. The Streamlined Filing Compliance Procedures provide a potential route for qualifying Americans who need to catch up on overdue returns and foreign account reporting.
Example: An American Who Grew Up Abroad
Consider someone who was born in New York but moved to Australia at age two.
They have lived and worked in Australia for 30 years, hold an Australian passport, and have never filed US taxes.
They recently discovered that they remain a US citizen but have no SSN.
Their next steps generally involve:
- Confirming their US citizenship and whether an SSN was previously issued.
- Applying for an SSN if they have never received one.
- Reviewing their US tax filing and foreign financial reporting obligations.
- Determining whether they qualify for the Streamlined Filing Compliance Procedures.
- Preparing the required overdue returns and information reports.
The appropriate filing approach depends on their circumstances, including the reasons for prior noncompliance.
Does Not Having an SSN Remove Your US Tax Obligations?
No. A missing Social Security number does not automatically eliminate federal income tax filing requirements. US citizens generally remain subject to US tax rules regardless of where they live or whether they have an SSN.
For example, an American who earns income entirely from a foreign employer may still need to report that income to the IRS. Similarly, US citizens with foreign financial accounts may be subject to FBAR reporting requirements if their combined account balances exceed $10,000 at any point during the year.
A missing SSN is an administrative issue that should be addressed, not a general exemption from US tax compliance.
Catch Up on Overdue US Returns
Our team prepares Streamlined Filing packages for Americans abroad, including first-time filers.
Common Mistakes When Filing Without an SSN
Several misunderstandings can cause delays or additional complications.
- Applying for an ITIN despite being eligible for an SSN. US citizens generally must use an SSN.
- Assuming foreign citizenship eliminates US filing requirements. Dual citizens may still have US tax obligations.
- Submitting Streamlined Filing documents without a required SSN. This can affect eligibility for penalty relief.
- Applying for a second SSN. Individuals who previously received a number should recover their existing number.
- Assuming a foreign spouse always needs an ITIN. The requirement depends on the filing circumstances.
- Waiting until the filing deadline to start an SSN application. First-time overseas applications may require additional documentation and processing time.
Resolving identification issues early can make the eventual tax filing process considerably easier.
