Lesbian, gay, bisexual, transgender, and queer (LGBTQ) rights in the U.S. state of Indiana have been shaped by both state and federal law. These evolved from harsh penalties established early in the state's history to the decriminalization of same-sex activity in 1977 and the legalization of same-sex marriage in 2014. Indiana was subject to an April 2017 federal court ruling that discrimination based on sexual orientation is tantamount to discrimination on account of "sex", as defined by the Civil Rights Act of 1964. The ruling establishes sexual orientation as a protected characteristic in the workplace, forbidding unfair discrimination, although Indiana state statutes do not include sexual orientation or gender identity among its categories of discrimination.

Historically, Indiana had severe penalties in place for same-sex activity, including the death penalty for sodomy, until decriminalization in 1976. Same-sex marriages have been recognized and performed in Indiana since 2014, when the U.S. Supreme Court refused to consider an appeal in the case of Baskin v. Bogan. There had been regular attempts to adopt a constitutional amendment defining marriage as a union between a man and a woman since 2004, but they have failed. Indiana previously tracked bias crimes, including those based on sexual orientation, but did not enhance sentencing for such crimes until April 2019 when the state passed a hate crimes law allowing judges to impose harsher sentences for crimes committed with intent to harm or intimidate based on perceived or actual characteristics.

In 2004, Governor Joe Kernan issued an executive order protecting state employees from discrimination based on sexual orientation and gender identity, which was further reinforced in 2005 by Governor Mitch Daniels, though state statutes do not include these categories among its non-discrimination grounds. Indiana's 2015 Religious Freedom Restoration Act faced significant backlash from groups which argued it targeted LGBT rights and was later clarified to prevent discrimination based on sexual orientation and gender identity.

In May 2023, Indiana passed HB 1608, prohibiting classroom instruction on "human sexuality" from kindergarten to third grade and requiring schools to inform parents if a minor student requests a change in name or pronouns. A federal judge upheld an injunction in August 2023, preventing Indiana schools from restricting bathroom access for transgender students. In March 2023, Indiana passed a bill banning gender-affirming healthcare for minors, which took effect in February 2024, and in April 2023 the state banned gender-affirming healthcare within prisons. Indiana statutes allow single LGBT persons and same-sex couples to adopt. A federal ruling in 2016 required the state to list both same-sex parents on birth certificates. In May 2023, the Governor signed a law prohibiting local governments from enacting bans on conversion therapy, effectively keeping the practice legal statewide. In March 2025, Governor Mike Braun signed an executive order defining sex solely as assigned sex at birth, resulting in the Indiana Department of Health to ban gender marker changes on birth certificates.

A 2022 Public Religion Research Institute poll found that 67% of Indiana residents supported same-sex marriage, 78% supported anti-discrimination laws covering sexual orientation and gender identity, and 57% opposed allowing public businesses to refuse service to LGBTQ people based on religious beliefs.

In 1795, Indiana as part of the Northwest Territory passed the "buggery" law, which punished male sodomy with death. In 1807, the Indiana Territory enacted a criminal code which included a sodomy provision, eliminating the gender-specifics (meaning it would be applicable to both heterosexual and homosexual conduct), reducing the penalty to one to five years' imprisonment, a fine of 100 to 500 dollars, up to 500 lashes and a permanent loss of civil rights. Sodomy was briefly legal between the years 1852 and 1881, as a new criminal code was passed without any mention to sodomy. In 1881, the state passed a statute outlawing anal intercourse, fellatio (oral sex) as well as masturbation under the age of 21 (which was labelled "self-pollution") for both heterosexuals and homosexuals. Penalty was set at "not more than fourteen years nor less than two years". In the 1923 case of Young v. State, the Indiana Supreme Court unanimously ruled that cunnilingus was also criminal, and in 1939, in Connell v. State, rejected contentions had the statute applied only to homosexual sexual activity.

In 1949, the state passed a psychopathic offender law, under which any person above 16 years of age suffering from a "mental disorder" "coupled with criminal propensities to the commission of sex offenses" would be labelled a "criminal sexual psychopathic person". Those convicted of sodomy would not be able to leave correctional institutions until their "full recovery of criminal psychopathy". A law review article in 1947 showed 160 commitments under the law, of which 60 (38%) were for sodomy and none of the offenders had been a woman. A majority of these commitments were for heterosexual conduct. In 1959, an amendment to the law meant that those refusing to cooperate with examining psychiatrists could be held in contempt of court. In 20 years of operation, only 10 "consensual adult homosexuals" were committed under the law. The law was upheld by the Indiana Supreme Court in 1968 in State ex rel. Haskett v. Marion County Criminal Court, Division One et al. In 1971, the Indiana General Assembly amended the law, removing sodomy from the list of triggering offenses, if consensual and committed with an adult person.

In 1967, in a divided 3-2 ruling, the Indiana Supreme Court upheld as constitutionally sufficient an indictment charging the "abominable and detestable crime against nature". Justice Amos W. Jackson dissented, writing that the