For federal tax purposes, individuals of the same sex are considered lawfully married if they are legally married in a jurisdiction that recognizes such marriages. This determination is based on the laws of the state, possession, or territory of the United States, or a foreign jurisdiction where the marriage was entered into. The IRS recognizes these marriages regardless of whether the couple resides in a jurisdiction that does not recognize the validity of same-sex marriages.
The IRS has established a general rule that a marriage of same-sex individuals will be recognized for federal tax purposes if it was validly entered into in a jurisdiction whose laws authorize the marriage of two individuals of the same sex. This includes both domestic and foreign jurisdictions. The domicile of the married couple does not affect the recognition of the marriage for federal tax purposes.
Additionally, the terms "spouse," "husband and wife," "husband," and "wife" include individuals married to a person of the same sex if they are lawfully married under state law. However, these terms do not include individuals in registered domestic partnerships, civil unions, or other similar formal relationships that are not denominated as marriage under the laws of the state, possession, or territory where the relationship was entered into.
This recognition of same-sex marriages for federal tax purposes has been in effect since September 16, 2013, following the IRS's issuance of Revenue Ruling 2013-17, which was influenced by the Supreme Court's decision in United States v. Windsor. The ruling ensures that same-sex couples legally married in jurisdictions that authorize such marriages are treated as married for all federal tax purposes, regardless of their state of domicile.
Sources:
Rev. Rul. 2013-17
§ 301.7701-18. Definitions; spouse, husband and wife, husband, wife, marriage.
Notice 2017-15
§ 7701. Definitions
Complying With IRS Guidance on Same-Sex Marriage
Publication 501 (2023)
