Yes—if Article IV makes you a Canadian treaty resident and you are not also a U.S. citizen, you must file 2025 Form 1040-NR and attach Form 8833; otherwise your residence return is Form 1040.
“I am a Canadian citizen who was in the US for all 365 days of 2025, meeting the Substantial Presence Test. I remained a Canadian tax resident and filed my Canadian T1. I do not have a green card. Do I need to file a Form 1040-NR to take a treaty-based nonresident position, and should I attach Form 8833?”
Summary
Meeting the Substantial Presence Test does not end the analysis: the treaty can still change how you compute U.S. income tax. The paperwork is clear once you establish which country wins Article IV’s ordered test.
Your return route depends on the Canada–U.S. treaty result—and, separately, whether you are also a U.S. citizen.
If you are a , Article IV(2) assigns you to Canada, and you are not a U.S. citizen, take the treaty position by filing 2025 Form 1040-NR, computing U.S. tax as a , and attaching Form 8833. This filing is required even if you otherwise would not have needed a U.S. income-tax return.
If the ordered Article IV tests point to the United States, you cannot take the treaty-based nonresident position. File Form 1040 as a resident alien; IRS Publication 519 says a resident alien reports worldwide income.
The dual-resident-alien procedure in 26 CFR 301.7701(b)-7 does not apply, and the treaty’s saving clause generally allows the United States to tax its citizens as though the treaty did not exist. The general treaty-residence switch to Form 1040-NR is therefore not your route, although particular treaty benefits expressly excepted from the saving clause can be separate questions.
As of August 21, 2026, you are timely only if you obtained the applicable extension; otherwise file promptly and address the late disclosure.
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Watch out for
Next steps
These steps establish your treaty residence first, then put that result on the correct 2025 U.S. return.
Before choosing a U.S. form
Apply Article IV(2) in order
Decide permanent home first. If you had a home in both countries or neither, decide your centre of vital interests; if that cannot be determined, decide habitual abode; only if habitual abode was in both or neither does Canadian citizenship decide. Your 365 U.S. days do not let you skip the earlier steps.
Requirements
After the treaty analysis
Choose Form 1040-NR or Form 1040
If Article IV assigns you to Canada and you are not a U.S. citizen, prepare the 2025 Form 1040-NR at https://www.irs.gov/pub/irs-prior/f1040nr--2025.pdf. If Article IV assigns you to the United States—or if the U.S.-citizen saving-clause branch applies—use the 2025 Form 1040 resident-return route instead.
Requirements
Only for the Canadian treaty-resident route
Complete and attach Form 8833
Use https://www.irs.gov/pub/irs-pdf/f8833.pdf. On line 1 identify Canada and Article IV; on line 2 identify Internal Revenue Code section 7701(b) as the domestic residence provision modified; on line 6 explain the treaty position, summarize the permanent-home/relations/habitual-abode facts, and list the affected amounts. Attach Form 8833 to Form 1040-NR even if no return otherwise would have been required.
Requirements
Time-sensitive on August 21, 2026
File by the applicable extended date—or file now
The original deadline was April 15, 2026 if you had employee wages subject to U.S. withholding, otherwise June 15, 2026. A timely Form 4868 extends those dates to October 15 and December 15, respectively. If extended, file by that date; if not, file now. You may e-file without mailing. For a paper return without payment, mail to Department of the Treasury, Internal Revenue Service, Austin, TX 73301-0215 USA; with payment, mail to Internal Revenue Service, P.O. Box 1303, Charlotte, NC 28201-1303 USA.
Requirements
If no timely extension exists
Add a sworn penalty-waiver statement if disclosure is late
Form 8833 warns of a possible $1,000 individual penalty. With the late filing, include a written request under 26 CFR 301.6712-1 stating every fact showing lack of willful neglect and declare under penalties of perjury that the statement is true; the regulation allows the IRS to waive the penalty in whole or part on that showing.
Requirements
Legal sources
This answer rests on the Canada–U.S. Income Tax Convention, current Treasury regulations in the eCFR, IRS Publication 519, and the IRS instructions for Forms 1040-NR and 8833.
Canada–U.S. Convention Art. IV
This is the ordered Canada–U.S. treaty test that decides which country is your treaty residence.
Article IV(2)(a)–(d)
Where by reason of the provisions of paragraph 1 an individual is a resident of both Contracting States, then his status shall be determined as follows: (a) he shall be deemed to be a resident of the Contracting State in which he has a permanent home available to him; if he has a permanent home available to him in both States or in neither State, he shall be deemed to be a resident of the Contracting State with which his personal and economic relations are closer (centre of vital interests); (b) if the Contracting State in which he has his centre of vital interests cannot be determined, he shall be deemed to be a resident of the Contracting State in which he has an habitual abode; (c) if he has an habitual abode in both States or in neither State, he shall be deemed to be a resident of the Contracting State of which he is a citizen; and (d) if he is a citizen of both States or of neither of them, the competent authorities of the Contracting States shall settle the question by mutual agreement.
26 CFR 301.7701(b)-7
A dual-resident alien computing U.S. tax as a nonresident must timely file Form 1040-NR and attach the prescribed statement.
(b)
An alien individual described in paragraph (a) of this section who determines his or her U.S. tax liability as if he or she were a nonresident alien shall make a return on Form 1040NR on or before the date prescribed by law (including extensions) for making an income tax return as a nonresident. The individual shall prepare a return and compute his or her tax liability as a nonresident alien. The individual shall attach a statement (in the form required in paragraph (c) of this section) to the Form 1040NR.
Form 8833
The IRS’s current Form 8833 instructions identify Form 8833 as the required attachment for this exact choice.
Dual-resident taxpayer, page 4
If you are eligible to be treated as a resident of the foreign country pursuant to the applicable income tax treaty and you choose to claim benefits as a resident of such foreign country, you must file Form 1040-NR, U.S. Nonresident Alien Income Tax Return, with Form 8833 attached.
26 CFR 301.6114-1
Treaty disclosure can require a return even when no tax return would otherwise be required.
(a)(1)(ii)
If a return of tax would not otherwise be required to be filed, a return must nevertheless be filed for purposes of making the disclosure required by this section.
2025 Instructions for Form 1040-NR
These are the two possible original due dates for your 2025 Form 1040-NR.
When and Where Should You File?, page 12
If you were an employee and received wages subject to U.S. income tax withholding, file Form 1040-NR by the 15th day of the 4th month after your tax year ends. A return for the 2025 calendar year is due by April 15, 2026. If you didn’t receive wages as an employee subject to U.S. income tax withholding, file Form 1040-NR by the 15th day of the 6th month after your tax year ends. A return for the 2025 calendar year is due by June 15, 2026.
IRS Publication 519 (2025)
A timely Form 4868 extends the filing deadline to October 15 or December 15, depending on the original deadline.
When To File, page 49
If you cannot file your return by the due date, file Form 4868 or use one of the electronic filing options explained in the instructions for Form 4868. For the 2025 calendar year, this will extend the due date to October 15, 2026. If your regular due date is June 15, 2026, this will extend the due date to December 15, 2026. You must file the extension by the regular due date of your return.
IRS Publication 519 (2025)
An extension delays filing, not payment, so unpaid tax can accrue interest and penalties from the original date.
When To File, page 49
An automatic 6-month extension to file does not extend the time to pay your tax. If you do not pay your tax by the original due date of your return, you will owe interest on the unpaid tax and may owe penalties.
Form 8833; IRC 6712
Failure to disclose the position on Form 8833 may carry a $1,000 individual penalty.
page 1
Failure to disclose a treaty-based return position may result in a penalty of $1,000 ($10,000 in the case of a C corporation) (see section 6712).
26 CFR 301.6712-1
The treaty-disclosure penalty can be waived if the required written, sworn facts establish lack of willful neglect.
(b)
Pursuant to the authority contained in section 6712(b) of the Code, the penalty imposed by paragraph (a) of this section may be waived, in whole or in part, if it is established to the satisfaction of the Assistant Commissioner (International), the District Director or the Director of the Internal Revenue Service Center that the taxpayer's failure to disclose the required information was not due to willful neglect. An affirmative showing of lack of willful neglect must be made in the form of a written statement that sets forth all the facts alleged to show lack of willful neglect and contains a declaration by such person that the statement is made under the penalties of perjury.
26 CFR 301.7701(b)-7
Treaty nonresident treatment generally changes income-tax computation only, not every other Code purpose.
(a)(3)
Generally, for purposes of the Internal Revenue Code other than the computation of the individual's United States income tax liability, the individual shall be treated as a United States resident.
IRS Publication 519 (2025)
If the treaty route does not apply, resident-alien treatment means reporting worldwide income on Form 1040.
page 25
Resident aliens should file Form 1040 or 1040-SR at the address shown in the Instructions for Form 1040. This means that their worldwide income is subject to U.S. tax and must be reported on their U.S. tax return.
Canada–U.S. Convention Art. XXIX
The saving clause is why a possible U.S.-citizenship fact creates a separate branch.
Article XXIX(2)
Except as provided in paragraph 3, nothing in the Convention shall be construed as preventing a Contracting State from taxing its residents (as determined under Article IV (Residence)) and, in the case of the United States, its citizens (including a former citizen whose loss of citizenship had as one of its principal purposes the avoidance of tax, but only for a period of ten years following such loss) and companies electing to be treated as domestic corporations, as if there were no convention between the United States and Canada with respect to taxes on income and on capital.
These are the official rules as published on the cited dates; tax rules, forms, and filing procedures can change.
This is general information about official processes, not legal advice, and SettleKit is not a law firm.
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