Ego-dystonic sexual orientation is a highly controversial mental health diagnosis that was included in the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (DSM) from 1980 to 1987 (under the name ego-dystonic homosexuality) and in the World Health Organization's (WHO) International Classification of Diseases (ICD) from 1990 to 2019. Individuals could be diagnosed with ego-dystonic sexual orientation if their sexual orientation or attractions were at odds with their idealized self-image, causing anxiety and a desire to change their orientation or become more comfortable with it. It describes not innate sexual orientation itself, but a conflict between the sexual orientation a person wishes to have and their actual sexual orientation.

The addition of ego-dystonic homosexuality to the DSM-III in 1980 constituted a political compromise between those who believed that homosexuality was a pathological condition and those who believed it was a normal variant of sexuality. Under pressure from members of the psychiatry and psychology fields and mounting scientific evidence that the desire to be heterosexual is a common phase in a gay, lesbian, or bisexual person's identity development rather than an indication of mental illness, the diagnosis was removed seven years later, but ego-dystonic sexual orientation was added to the ICD-10 in 1990. Leading up to the publication of the ICD-11, a WHO-appointed working group recommended its deletion, due to a lack of clinical utility, a lack of usefulness in public health data, and the potential for negative consequences. The ICD-11, which was approved in 2019 and went into effect in January 2022, does not include any diagnostic categories that can be applied to people on the basis of sexual orientation, bringing the ICD in line with the DSM-5.

The diagnostic categories of ego-dystonic homosexuality and ego-dystonic sexual orientation legitimized controversial sexual orientation change efforts, most notably the practice of conversion therapy, even as such practices were being increasingly scientifically debunked. After an extensive review of the research literature, the WHO working group concluded that there are no evidence-based treatments for ego-dystonic sexual orientation, and individuals who exhibit distress or concern over their sexual orientation do not require any unique therapeutic interventions other than common treatments for distress, anxiety, depression, and other conditions.