Sexual repression is a state in which a person is prevented from expressing their own sexuality or sexual orientation. Sexual repression can be caused by an emotional conflict, in which a person feels guilt, shame, or distress regarding their natural sexual impulses. These feelings of emotional distress can be exacerbated by outside factors, such as family, religion, and peer pressure. Sexual repression is often synonymous with internalized homophobia, in which a gay, lesbian, or bisexual person feels the need to suppress their own homosexual impulses and conform to heterosexual norms. Sexual repression can also be caused by external oppression, in which the laws of a society prevent someone from expressing their sexuality freely.

Defining characteristics and practices associated with sexual repression vary between societies and different historical periods. The behaviours and attitudes constituting sexual repression differ across cultures, religious communities and moral systems. Sexual repression can largely be categorised as physical, mental or an amalgam of both.

Sexual repression is enforced through legislation in certain countries, many of which are located in the Middle East and North Africa region, and South Asia. Common practices associated with the practice include female genital mutilation. Individuals believed to have engaged in behaviours contradicting social, religious or cultural expectations of sexual repression, such as same-sex sexual activity, may be punished through honor killings, persecution or the death penalty.

Sigmund Freud was the first to use the term 'sexual repression' widely, and argued that it was one of the roots of many problems in Western society. Freud believed that people's naturally strong instincts toward sexuality were repressed by people in order to meet the constraints imposed on them by civilized life. Among many others, Freud believed renowned artist Leonardo da Vinci to have been a repressed homosexual, who he believed "sublimated" his sexual desires so as to achieve artistic brilliance. However, Freud's ideas about sexual repression have been subject to heavy criticism. According to sex therapist Bernard Apfelbaum, Freud did not base his belief in universal innate, natural sexuality on the strength of sexual desire he saw in people, but rather on its weakness.

In some periods of Indian history, anaphrodisiacs were utilised in order to lower libido.

In contemporary society, medication may be prescribed to registered sex offenders in order to lower the libido and ensure that further offences are less likely.

Sexual repression is a recurring prohibition in many religious contexts.^{[citation needed]}

Most forms of Christianity discourage homosexual behavior.