Same-sex marriage has been legally recognized in Wyoming since October 21, 2014. The U.S. state of Wyoming had previously prohibited state recognition of same-sex marriages by statute since 1977 and had enacted a more explicit ban in 2003. An attempt to enact legislation recognizing domestic partnerships as an alternative to marriage for same-sex couples failed in 2013. On October 17, 2014, a federal district court found the state's ban on same-sex marriage unconstitutional. Its ruling took effect on October 21 when state officials notified the court that they would not appeal the decision.

On January 28, 2011, the House Judiciary Committee rejected a bill to legalize same-sex civil unions.^[15]

On January 14, 2013, legislators filed a bill to legalize same-sex marriage in Wyoming by defining marriage as a civil contract between "two natural persons". On January 28, a House committee defeated the marriage bill by a vote of 5–4.^[16] A domestic partnership bill allowing same-sex couples to "obtain the rights, responsibilities, protections and legal benefits provided in Wyoming for immediate family members" was passed by a House committee on a vote of 7–2 on January 28. Legislators who favored same-sex marriage supported the legislative tactic of offering the alternatives.^[17] Governor Matt Mead said he favored domestic partnerships.^[18] The House rejected the bill on January 30, 2013 in a 24–35 vote.^[19]

The House considered a same-sex marriage bill in 2014 but defeated it on February 13, 2014 by a vote of 17–41.^[20]

Wyoming Governor Matt Mead said that despite action by the U.S. Supreme Court on October 6, 2014, which left standing as binding precedent on courts in Wyoming rulings of the Tenth Circuit Court of Appeals that found bans on same-sex marriage unconstitutional, the Attorney General, Peter K. Michael, "will continue to defend Wyoming's constitution defining marriage between a man and a woman", mistakenly referring to the State Constitution, which does not define marriage. Clerks in Laramie, Natrona and Teton counties said they had received inquiries about issuing marriage licenses to same-sex couples, but were waiting for a change in state law or an order from a judge.^[21]

On June 26, 2015, the U.S. Supreme Court ruled in Obergefell v. Hodges that same-sex couples have a constitutional right to marry under the Due Process and Equal Protection clauses of the Fourteenth Amendment. The decision legalized same-sex marriage nationwide in the United States.

In March 2017, the Wyoming Supreme Court issued a ruling 3–2 discipling a judge, Ruth Neely from Pinedale, who had, in violation of her oath of office, said she would not marry same-sex couples. Neely had informed a local newspaper in 2015 that she would "not be able to" perform the marriages due to her religious beliefs, and compared homosexuality to alcoholism and theft. The Wyoming Commission on Judicial Conduct and Ethics opened an investigation into her, and concluded that Neely had violated the Wyoming Code of Judicial Conduct and recommended that she be removed from her judicial position: "Judges do not enjoy the same freedom to proselytize their religious beliefs as ordinary citizens." The commission said that her statement amounted to a conclusion that "adherence to the law is optional".^[34] Neely appealed directly to the Supreme Court in August 2016. The court rejected Neely's claims but modified her penalty, issuing instead a "public censure" and demanding that she either marry all couples, regardless of sexual orientation, or none.^[35]

On February 14, 2018, two Republican representatives, Lars Lone and Roy Edwards, introduced the Marriage and Constitution Restoration Act to the Wyoming House of Representatives. The bill sought to reenact the state's same-sex marriage ban, and ban the state's political subdivisions from "granting, endorsing, respecting or recognizing any marriage not between a man and woman". The bill would have thus been in violation of Obergefell and the U.S. Constitution. House lawmakers refused to consider the bill and killed it merely two days after its introduction to the House.^[36][37]

Same-sex marriage is recognized on the Wind River Indian Reservation, a Native American reservation shared by the Eastern Shoshone and the Northern Arapaho peoples. The first same-sex marriage at the Shoshone and Arapaho Tribal Court in Fort Washakie was registered on November 14, 2014 for Saun and Renee Allen.^[38]

While there are no records of same-sex marriages as understood from a Western perspective being performed in Native American cultures, there is evidence for identities and behaviours that may be placed on the LGBT spectrum. Many of these cultures recognized two-spirit individuals who were born male but wore women's clothing and performed everyday household work and artistic handiwork which were regarded as belonging to the feminine sphere.^[39] Arapaho culture has traditionally regarded two-spirit people as "esteemed persons with special spiritual powers". They are known as hoxúx (pronounced [hɔxʊ́x], plural: hoxúxono) in the Arapaho language. Many hoxúxono married cisgender men without indication of polygyny.^[39] The two-spirit status thus allowed for marriages between two biological males to be performed in the tribe. In the eastern dialect of the Shoshone language, two-spirit people, who "act[ed] like women" and did women's work, are known as waipenaiteN (pronounced [ˈwai̯pːɨ̃nai̯tːɨn]),^[40] but unlike the Arapaho hoxúx, they would never marry.^[39]

The Williams Institute estimated in September 2014 that if marriage were extended to same-sex couples in Wyoming, the state would see an economic boost of $2.4 million over the course of three years. This net impact would be the result of savings in expenditures on state means-tested public benefit programs and an increase in state income and sales tax revenue.^[41]

Data from the 2000 U.S. census showed that 807 same-sex couples were living in Wyoming. By 2005, this had increased to 1,044 couples, likely attributed to same-sex couples' growing willingness to disclose their partnerships on government surveys. Same-sex couples lived in all counties of the state and constituted 0.7% of coupled households and 0.4% of all households in the state. Most couples lived in Natrona, Laramie and Fremont counties, but the counties with the highest percentage of same-sex couples were Niobrara (0.69% of all county households) and Fremont (0.65%). Same-sex partners in Wyoming were on average younger than opposite-sex partners, and less likely to be employed. The average and median household incomes of same-sex couples were lower than different-sex couples, and same-sex couples were also far less likely to own a home than opposite-sex partners. 20% of same-sex couples in Wyoming were raising children under the age of 18, with an estimated 501 children living in households headed by same-sex couples in 2005.^[42]

On October 21, 2015, exactly one year after the ruling in Guzzo v. Mead, the Vital Statistics Services office of the Wyoming Department of Health estimated that 201 marriage licenses had been issued to same-sex couples in the state. This constituted about 5% of the 3,850 marriage licenses issued in Wyoming in that time.^[43]

The 2020 U.S. census showed that there were 681 married same-sex couple households (271 male couples and 410 female couples) and 473 unmarried same-sex couple households in Wyoming.^[44]

A July 2013 Public Policy Polling survey found that 57% of Wyoming voters thought same-sex marriage should be illegal, while 32% thought it should be legal and 11% were not sure. A separate question on the same survey found that 64% of respondents supported legal recognition for same-sex couples, with 28% supporting same-sex marriage, 36% supporting civil unions but not marriage, 32% opposing all legal recognition and 3% not sure.^[45]

A University of Wyoming survey conducted between October 13 and October 28, 2014 found that 53% of respondents agreed that "homosexual couples should be allowed to get married", while 39% disagreed and 8% declined to answer.^[46] This was a big change in comparison to 2004, when 24% of Wyoming respondents supported same-sex marriage.^[27]

2015 and 2016 polls from the Public Religion Research Institute (PRRI) found that 48% and 49% of Wyoming residents supported same-sex marriage, respectively.^[47][48] In 2017, the PRRI placed support for same-sex marriage in Wyoming at 62%, while opposition stood at 30%, and 8% were undecided.^[49] A 2020 PRRI survey showed that 75% of Wyoming respondents supported same-sex marriage, while 17% were opposed and 8% were undecided or did not answer.^[50] According to a survey conducted by the same polling organization between March 11 and December 14, 2022, 62% of Wyoming respondents supported same-sex marriage, while 38% were opposed.^[51]

• LGBT rights in Wyoming
• Same-sex marriage in the United States