Rape is a type of sexual assault involving sexual intercourse, or other forms of sexual penetration, carried out against a person without their consent. The act may be carried out by physical force, coercion, abuse of authority, or against a person who is incapable of giving valid consent, such as one who is unconscious, incapacitated, has an intellectual disability, or is below the legal age of consent (statutory rape). The term rape is sometimes casually used interchangeably with the term sexual assault.

The rate of reporting, prosecuting and convicting for rape varies between jurisdictions. Internationally, the incidence of rapes recorded by the police during 2008 ranged, per 100,000 people, from 0.2 in Azerbaijan to 92.9 in Botswana with 6.3 in Lithuania as the median. Worldwide, reported instances of sexual violence, including rape, are primarily committed by males against females. Rape by strangers is usually less common than rape by people the victim knows, and male-on-male prison rapes are common and may be the least reported forms of rape.

Widespread and systematic rape (e.g., war rape) and sexual slavery can occur during international conflict. These practices are crimes against humanity and war crimes. Rape is also recognized as an element of the crime of genocide when committed with the intent to destroy, in whole or in part, a targeted ethnic group.

People who have been raped can be traumatized and develop post-traumatic stress disorder. Serious injuries can result along with the risk of sexually transmitted infections. Female victims face the additional risk of pregnancy. A person may face violence or threats from the rapist, and, sometimes, from the victim's family and relatives.

The term rape originates from the Latin rapere (supine stem raptum), "to snatch, to grab, to carry off". In Roman law, the carrying off of a woman by force, with or without intercourse, constituted "raptus". In Medieval English law the same term could refer to either kidnapping or rape in the modern sense of "sexual violation". The original meaning of "carry off by force" is still found in some phrases, such as "rape and pillage", or in titles, such as the stories of the Rape of the Sabine Women and The Rape of Europa or the poem The Rape of the Lock, which is about the theft of a lock of hair.

Rape is defined in most jurisdictions as sexual intercourse, or other forms of sexual penetration, committed by a perpetrator against a victim without their consent. The definition of rape is inconsistent between governmental health organizations, law enforcement, health providers, and legal professions. It has varied historically and culturally. Originally, rape had no sexual connotation and is still used in other contexts in English. In Roman law, it or raptus was classified as a form of crimen vis, "crime of assault". Raptus referred to the abduction of a woman against the will of the man under whose authority she lived, and sexual intercourse was not a necessary element. Other definitions of rape have changed over time. The International Criminal Tribunal for the former Yugoslavia considered rape as a crime that required coercion or force or threat of force against the victim or a third person.

Until 2012, the Federal Bureau of Investigation (FBI) considered rape a crime solely committed by men against women. In 2012, they changed their definition from "The carnal knowledge of a female forcibly and against her will" to "The penetration, no matter how slight, of the vagina or anus with any body part or object, or oral penetration by a sex organ of another person, without the consent of the victim." The updated definition still excluded a man being forced to penetrate a woman from the definition of rape, which is generally recognized as the academic definition of rape. However, it recognized any gender of victim and perpetrator and that rape with an object can be as traumatic as penile/vaginal rape. The bureau further describes instances when the victim is unable to give consent because of mental or physical incapacity. It recognizes that a victim can be incapacitated by drugs and alcohol and unable to give valid consent. The definition does not change federal or state criminal codes or impact charging and prosecution on the federal, state, or local level; it rather means that rape will be more accurately reported nationwide.

Health organizations and agencies have also expanded rape beyond traditional definitions. The World Health Organization (WHO) defines rape as a form of sexual assault, while the Centers for Disease Control and Prevention (CDC) includes rape in their definition of sexual assault; they term rape a form of sexual violence. The CDC lists other acts of coercive, non-consensual sexual activity that may or may not include rape, including drug-facilitated sexual assault, acts in which a victim is made to penetrate a perpetrator or someone else, intoxication where the victim is unable to consent (due to incapacitation or being unconscious), non-physically forced penetration which occurs after a person is pressured verbally (by intimidation or misuse of authority to force to consent), or completed or attempted forced penetration of a victim via unwanted physical force (including using a weapon or threatening to use a weapon). The Veterans Health Administration (VHA) has implemented universal screening for what has been termed "military sexual trauma" (MST) and provides medical and mental health services free of charge to enrolled veterans who report MST (Title 38 United States Code 1720D; Public Law 108–422).