Same-sex marriage has been legal in Wisconsin since October 6, 2014, when the U.S. Supreme Court refused to consider an appeal in the case of Wolf v. Walker.

Several Native American tribes recognized individuals who would act, behave and live as the opposite biological sex, nowadays also called "two-spirit".

Wisconsin was part of the Michigan Territory in 1836, when it adopted a prohibition on sodomy that applied to both heterosexual and homosexual sexual activities, excluding cunnilingus.

[4] In the 1950s, following a series of high-profile sex crimes, Wisconsin criminalized cunnilingus and increased the penalties for "sexual perversion" to five years' imprisonment.

[3] In 1913, the Wisconsin Legislature passed a law providing for the possible sterilization of criminals in state institutions, including those convicted under the sodomy statute.

[3] In 1966, the Wisconsin Young Democrats approved a resolution urging "the abolition of all legal restriction on sexual relations between consenting adults which do not violate the rights of others", one of the first major political organizations in the United States to do so.

[7] In order to obtain sufficient votes among legislators, the bill stated that Wisconsin did not approve of "any sexual conduct outside of the institution of marriage.

The registry, Chapter 770, was established in 2009 by a provision included in the state's biennial budget bill and signed into law by Democratic Governor Jim Doyle.

[13] The registry survived the court challenge, originally Appling v. Doyle[14] On July 31, 2014, the Wisconsin Supreme Court ruled unanimously in the case, now known as Appling v. Walker, that the registry was constitutional, citing statements made by proponents of the constitutional amendment at issue "that the Amendment simply would not preclude a mechanism for legislative grants of certain rights to same-sex couples".

[24] In September 2016, a federal judge ruled that the state must record the names of both same-sex parents on the birth certificates of their children.

The ruling came as a result of a lesbian couple who sued the Wisconsin Department of Health Services in 2015 after it refused to register both their names on the birth certificate of their son.

[26][27] In 1982, Wisconsin was the first state to ban discrimination based on sexual orientation in employment, housing, education, credit and all public accommodations.

[29][30] However, in January 2019, Governor Tony Evers in coordination with Fair Wisconsin issued Executive Order #1 which prohibiting discrimination on the basis of gender identity in government employment.

In May 2019, a federal judge ordered the program to be immediately extended to non-government employees as well, under the Equal Protection Clause of the 14th Amendment of the United States Constitution.

[46] In June 2023, an "extensive and comprehensive budget" bill passed both houses of the Wisconsin Legislature - that bans Medicaid (state based health insurance) coverage of sexual reassignment surgery and other gender-affirming healthcare to all individuals, regardless of age.

[47][48] In October 2023, Governor Evers said he would "veto any bill that makes Wisconsin a less welcoming, less inclusive, and less safe place for you to be who you are”, speaking to "LGBTQ folks — especially our trans kids".

A 2005 Wisconsin statute denying hormone therapy to prisoners undergoing sex reassignment surgery, the Inmate Sex Change Prevention Act, was ruled unconstitutional in a unanimous opinion in the case of Fields v. Smith by a three-judge panel of United States Court of Appeals for the Seventh Circuit on August 5, 2011.

[53] Since September 2023, the Milwaukee police department no longer lists gender (as well as race) of victims - to avoid misgendering transgender individuals within the future.

[55][56] In 2021 republicans introduced a bill which would have prohibited insurance companies from covering procedures related to gender affirming care for minors.

[72] Currently 14 communities in Wisconsin ban conversion therapy: Appleton, Cudahy, Eau Claire, Glendale, Kenosha, La Crosse, Madison, Milwaukee, Racine, Sheboygan, Shorewood, Sun Prairie, Superior and West Allis.

[73] In January 2023, the GOP blocked regulations within the Wisconsin Legislature - to make conversion therapy a code of conduct violation for marriage and family therapists, professional counselors and social workers.

[74] A 2017 Public Religion Research Institute (PRRI) opinion poll found that 66% of Wisconsin residents supported same-sex marriage, while 26% opposed it and 8% were unsure.