The relationship between religion and homosexuality has varied greatly across time and place, within and between different religions and denominations, with regard to different forms of homosexuality and bisexuality. The present-day doctrines of the world's major religions and their denominations differ in their attitudes toward these sexual orientations. Adherence to anti-gay religious beliefs and communities is correlated with the prevalence of emotional distress and suicidality in sexual minority individuals, and is a primary motivation for seeking conversion therapy.

Among the religious denominations which generally reject these orientations, there are many different types of opposition, ranging from quietly discouraging homosexual activity, explicitly forbidding same-sex sexual practices among their adherents and actively opposing social acceptance of homosexuality, supporting criminal sanctions up to capital punishment, and even to condoning extrajudicial killings. Religious fundamentalism often correlates with anti-homosexual bias. Psychological research has connected religiosity with homophobic attitudes and physical antigay hostility, and has traced religious opposition to gay adoption to collectivistic values (loyalty, authority, purity) and low flexibility in existential issues, rather than to high prosocial inclinations for the weak. Attitudes toward homosexuality have been found to be determined not only by personal religious beliefs, but by the interaction of those beliefs with the predominant national religious context—even for people who are less religious or who do not share their local dominant religious context. Many argue that it is homosexual actions which are sinful, rather than same-sex attraction itself. To this end, some discourage labeling individuals according to sexual orientation. Several organizations assert that conversion therapy can help diminish same-sex attraction.

Some adherents of many religions view homosexuality and bisexuality positively, and some denominations routinely bless same-sex marriages and support LGBT rights, a growing trend as much of the developed world enacts laws supporting LGBT rights.

Historically, some cultures and religions accommodated, institutionalized, or revered same-sex love and sexuality; such mythologies and traditions can be found around the world. While Hinduism does not condemn homosexuality exclusively, it does often have a negative view on sexual activity generally (especially for the upper class of monks and priests), and one can find numerous portrayals of homosexuality in Hindu literature and artworks. Also there is an important point to note that Hindus have a god or a symbol called Hari Hara which resembles both men and women. i.e Half man and half woman. Sikh wedding ceremonies are non-gender specific, and so same-sex marriage is possible within Sikhism.

Regardless of their position on homosexuality, many people of faith look to both sacred texts and tradition for guidance on this issue. However, the authority of various traditions or scriptural passages and the correctness of translations and interpretations are continually disputed.

Individuals who went against the traditional gender binary were heavily involved in the cult of Inanna, an ancient Mesopotamian goddess. During Sumerian times, a set of priests known as gala worked in Inanna's temples, where they performed elegies and lamentations. Men who became gala sometimes adopted female names and their songs were composed in the Sumerian eme-sal dialect, which, in literary texts, is normally reserved for the speech of female characters. Some Sumerian proverbs seem to suggest that gala had a reputation for engaging in anal sex with men. During the Akkadian Period, kurgarrū and assinnu were servants of Ishtar who dressed in female clothing and performed war dances in Ishtar's temples. Several Akkadian proverbs seem to suggest that they may have also had homosexual proclivities. Gwendolyn Leick, an anthropologist known for her writings on Mesopotamia, has compared these individuals to the contemporary Indian hijra. In one Akkadian hymn, Ishtar is described as transforming men into women. Some modern pagans include Inanna in their worship.

The Abrahamic religions of Judaism, Christianity and Islam, have traditionally forbidden sodomy, believing and teaching that such behavior is sinful. Today some denominations within these religions are accepting of homosexuality and inclusive of homosexual people, such as Reform Judaism, the United Church of Christ and the Metropolitan Community Church. Some Presbyterian, Anglican, Lutheran, and Methodist churches welcome members regardless of same-sex sexual practices, with some provinces allowing for the ordination and inclusion of gay and lesbian clerics, and affirmation of same-sex unions. Reform Judaism incorporates lesbian and gay rabbis and same-sex marriage liturgies, while Reconstructionist Judaism and Conservative Judaism in the US allows for lesbian and gay rabbis and same-sex unions.

The Torah (first five books of the Hebrew Bible) is the primary source for Jewish views on homosexuality. It states that: "[A man] shall not lie with another man as [he would] with a woman, it is תועבה (to'eba, "abomination")" (Leviticus 18:22). (Like many similar commandments, the stated punishment for willful violation is the death penalty, although in practice rabbinic Judaism no longer believes it has the authority to implement death penalties.)