A dual status individual is one who changes their tax status during the current year from a nonresident to a resident, or from a resident to a nonresident Dual status individuals determine their U.S. residency status under both the Internal Revenue Code and tax treaties. A dual status individual must file a dual status return as described in Publication 519, U.S. Tax Guide for Aliens. Dual-status individual – First-year choice An individual who did not meet either the green card test or the substantial presence test for the current year (for example, 2022) or the prior year (2021), and did not choose to be treated as a U.S. resident for part of the prior year (2021), but met the substantial presence test in the following year (2023), can choose to be treated as a U.S. resident for part of the current year (2022) and be taxed as a dual-status individual for the current year (2022) if certain tests are met. Refer to the First-Year Choice topic of Chapter 1 in Publication 519, U.S. Tax Guide for Aliens. Tax treaties Most tax treaties contain an article which defines tax residency for purposes of the treaty. Tax residency determined under the residency article of a tax treaty may differ from the residency provisions of the Internal Revenue Code. Dual-status individual married to a U.S. citizen or resident A dual status individual married to a U.S. citizen or resident may elect to file a joint income tax return with their spouse. Refer to Nonresident Spouse Treated as a Resident. Related Taxation of Resident Aliens Taxation of Nonresident Aliens Foreign Students and Scholars Tax Residency Status – First-Year Choice