A prisoner of war (POW, PoW, or PW) is a soldier, sailor, airman, marine, or any combatant who is imprisoned by an enemy power during or immediately after an armed conflict. By international law and several mutually agreed conventions, prisoners of war are required to be treated humanely and diplomatically. However, nations vary in their dedication to following these laws.

Article 4 of the Third Geneva Convention protects captured military personnel, some guerrilla fighters and certain civilians. It applies from the moment a prisoner is captured until he or she is released or repatriated. One of the main provisions of the convention makes it illegal to torture prisoners, and states that a prisoner can only be required to give his or her name, date of birth, rank and service number (if applicable).

The status of POW does not include unarmed non-combatants who are captured in time of war; they are protected by the Fourth Geneva Convention rather than the Third Geneva Convention.