Same-sex marriage in New Mexico

Same-sex marriage in New Mexico became legal statewide through a ruling by the New Mexico Supreme Court on December 19, 2013, requiring all county clerks to issue marriage licenses to qualified couples seeking marriage regardless of gender. Until then, same-sex couples could only obtain marriage licenses in certain counties of the state. Eight of 33 counties, covering 58% of the state's population, had begun issuing marriage licenses to same-sex couples in August and September 2013. New Mexico's marriage statute is not specific as to gender. It is the only state lacking a state statute or constitutional provision explicitly addressing same-sex marriage. Lacking a state law or judicial ruling concerning same-sex marriage prior to December 19, 2013, policy for the issuance of marriage licenses to same-sex couples was determined at the county level at the discretion of local issuing authorities. That is, some counties recognized same-sex marriage and issued marriage licenses to same-sex couples, while others did not. Despite the ruling by the New Mexico Supreme Court allowing same-sex marriages in the state, some of New Mexico's Native American tribes (most notably the Navajo Nation) continue to prohibit same-sex marriages within their jurisdictions and do not recognize same-sex marriages performed elsewhere.

A small number of same-sex marriages were licensed in Sandoval County in 2004. The practice was halted later that same day, February 20, after New Mexico Attorney General Patricia Madrid issued a ruling they were invalid.

On August 21, 2013, the county clerk of Doña Ana County, on his own initiative, began issuing marriage licenses to same-sex couples. Later in the month, three district judges ruling on separate lawsuits ordered first Santa Fe County, then Bernalillo County, and then Taos County, to issue marriage licenses to same-sex couples, with a fourth judge ordering the same in Grant County in September. A similar ruling was made in Los Alamos County, where the county clerk said she would not comply with the order until it was upheld on September 4, the first time a New Mexican judge affirmed a ruling for same-sex marriage after it had been challenged. Meanwhile, county clerks in San Miguel and Valencia counties altered marriage licenses for same-sex couples.

On August 29, 2013, New Mexico's county clerks voted unanimously to ask the New Mexico Supreme Court to rule on the legality of same-sex marriage and the Supreme Court held a hearing on their petition on October 23.

On December 19, 2013, that court issued a unanimous decision in Griego v. Oliver holding that marriage licenses must be issued to couples without respect to gender, making New Mexico the 17th state to legalize same-sex marriage.