Homosexuality in India has been documented throughout the history of the Indian subcontinent, and legal rights for homosexual individuals continue to be advanced in contemporary mainstream and regional politics. While homosexuality is legal and cohabitation is legally permitted with certain protections, same-sex marriage is not officially recognised at the national level.

Various ancient literary works and architectural depictions attest to the presence of homosexuality in early Indian societies. Historically, there were no known strict legal restrictions against homosexuality on the subcontinent until the advent of Islamic rule and subsequent European colonialism. Scholars note that the severe criminalisation of homosexuality was introduced through Islamic codes during the Mughal Empire, culminating in the 17th-century Fatawa-e-Alamgiri, and was later institutionalised nationwide by the British Raj through the 19th-century Indian Penal Code (IPC).

The modern criminalisation of homosexuality was established by Section 377 of the Indian Penal Code, imposing Victorian morality on Indian subjects in 1860. Following decades of legal challenges and social activism, the Supreme Court of India unanimously struck down the portions of Section 377 that criminalised consensual homosexual acts between adults in the landmark Navtej Singh Johar v. Union of India ruling on 7 September 2018. When the IPC was replaced by the Bharatiya Nyaya Sanhita in December 2023, language equivalent to Section 377 was omitted entirely.

Despite legal advancements, homophobia remains prevalent in parts of Indian society. Public discussion of homosexuality has historically been inhibited by cultural taboos surrounding sexuality. However, attitudes have shifted significantly in the 21st century. The Indian media, particularly cinema, has seen a rise in positive depictions of the LGBTQ community, and pride parades are regularly held in major cities across the country. Nevertheless, economic and social discrimination against LGBTQ people persists, and many face pressure from familial and religious institutions.

Estimates of the LGBTQ population in India vary widely due to the historical criminalisation and social stigma that discouraged self-reporting. In 2012, the Government of India submitted a conservative figure to the Supreme Court of "at least 2.5 million" based on self-declaration. In contrast, advocacy groups and global demographic models have estimated the population could be approximately 10% of the total population, or over 135 million people.

In 2021, multinational research firm Ipsos released a report based on a global survey that included a sample of nearly 50,000 individuals in India. The report indicated that 17% of the surveyed Indian population identified as non-heterosexual: 3% as gay or lesbian, 9% as bisexual, 1% as pansexual, 2% as asexual, and 2% as "other". Furthermore, 69% identified as heterosexual, with the remainder declining to answer.

There were no general legal restrictions on homosexuality or trans-sexuality for the general population of India prior to the early modern period. Several ancient texts, including the Arthashastra, mention a wide variety of sexual practices. While non-procreative sex was occasionally frowned upon in religious texts, it was treated as a minor offense compared to heterosexual adultery. Homosexual intercourse between men could generally be absolved by minor penances, such as bathing with one's clothes on.

The ninth chapter of the Kama Sutra, composed by Vātsyāyana around the 4th century CE, openly discusses oral sexual acts (auparistaka), homosexuality, and the sexual lives of transgender people (tritiya prakriti or third nature), presenting them as a natural variation of human sexuality rather than a moral failing. Similarly, Hindu mythology features various deities changing gender or engaging in same-sex unions, reflecting a fluid understanding of gender and sexuality in ancient Indian culture.