Wartime sexual violence is rape or other forms of sexual violence committed by combatants during an armed conflict, war, or military occupation often as spoils of war, but sometimes, particularly in ethnic conflict, the phenomenon has broader sociological motives. Wartime sexual violence may also include gang rape and rape with objects. It is distinguished from sexual harassment, sexual assaults and rape committed amongst troops in military service.

During war and armed conflict, rape is frequently used as a means of psychological warfare in order to humiliate and terrorize the enemy. Wartime sexual violence may occur in a variety of situations, including institutionalized sexual slavery, wartime sexual violence associated with specific battles or massacres, as well as individual or isolated acts of sexual violence.

Rape can also be recognized as genocide when it is committed with the intent to destroy, in whole or in part, a targeted group. International legal instruments for prosecuting perpetrators of genocide were developed in the 1990s, and the Akayesu case of the International Criminal Tribunal for Rwanda, between the International Criminal Tribunal for Yugoslavia and itself, which themselves were "pivotal judicial bodies [in] the larger framework of transitional justice", was "widely lauded for its historical precedent in successfully prosecuting rape as an instrument of genocide".

The Rome Statute of the International Criminal Court classifies rape, sexual slavery, enforced prostitution, and forced pregnancy as crimes against humanity and as war crimes.

There is no consensus definition of wartime sexual violence, as there is variance in what forms of violence are included in the definition and variance in which violence is considered conflict-related. The terms rape, sexual assault and sexual violence are frequently used interchangeably. The Explanatory Note of the Rome Statute, which binds the International Criminal Court, defines rape as follows:

The perpetrator invaded the body of a person by conduct resulting in penetration, however slight, of any part of the body of the victim or of the perpetrator with a sexual organ, or of the anal or genital opening of the victim with any object or any other part of the body.

and

The invasion was committed by force, or by threat of force or coercion, such as that caused by fear of violence, duress, detention, psychological oppression or abuse of power, against such person or another person, or by taking advantage of a coercive environment, or the invasion was committed against a person incapable of giving genuine consent.