The American Psychiatric Association votes 13–0 to remove homosexuality from its official list of psychiatric disorders, the Diagnostic and Statistical Manual of Mental Disorders.

The American Psychiatric Association (APA) is the main professional organization of psychiatrists and trainee psychiatrists in the United States, and the largest psychiatric organization in the world. It has more than 39,200 members who are involved in psychiatric practice, research, and academia representing a diverse population of patients in more than 100 countries. The association publishes various journals and pamphlets, as well as the Diagnostic and Statistical Manual of Mental Disorders (DSM). The DSM codifies psychiatric conditions and is used mostly in the United States as a guide for diagnosing mental disorders.

Homosexuality is romantic attraction, sexual attraction, or sexual behavior between people of the same sex or gender. As a sexual orientation, homosexuality is "an enduring pattern of emotional, romantic, and/or sexual attractions" exclusively to people of the same sex or gender. It also denotes identity based on attraction, related behavior, and community affiliation.

A mental disorder, also referred to as a mental illness, a mental health condition, or a psychiatric disability, is a behavioral or mental pattern that causes significant distress or impairment of personal functioning. A mental disorder is also characterized by a clinically significant disturbance in an individual's cognition, emotional regulation, or behavior, often in a social context. Such disturbances may occur as single episodes, may be persistent, or may be relapsing–remitting. There are many different types of mental disorders, with signs and symptoms that vary widely between specific disorders. A mental disorder is one aspect of mental health.

The Diagnostic and Statistical Manual of Mental Disorders is a publication by the American Psychiatric Association (APA) for the classification of mental disorders using a common language and standard criteria. It is an internationally accepted manual on the diagnosis and treatment of mental disorders, though it may be used in conjunction with other documents. Other commonly used principal guides of psychiatry include the International Classification of Diseases (ICD), Chinese Classification of Mental Disorders (CCMD), and the Psychodynamic Diagnostic Manual. However, not all providers rely on the DSM-5 as a guide, since the ICD's mental disorder diagnoses are used around the world, and scientific studies often measure changes in symptom scale scores rather than changes in DSM-5 criteria to determine the real-world effects of mental health interventions.