Parole, also known as provisional release, supervised release, or being on paper, is a form of early release of a prison inmate where the prisoner agrees to abide by behavioral conditions, including checking in with their designated parole officers, or else they may be rearrested and returned to prison.

Originating from the French word parole ('speech, spoken words' but also 'promise'), the term became associated during the Middle Ages with the release of prisoners who gave their word. This differs greatly from pardon, amnesty or commutation of sentence in that parolees are still considered to be serving their sentences, and may be returned to prison if they violate the conditions of their parole. It is similar to probation, the key difference being that parole takes place after a prison sentence, while probation can be granted in lieu of a prison sentence.

Parole of prisoners of war is "the agreement of persons who have been taken prisoner by an enemy that they will not again take up arms against those who captured them, either for a limited time or during the continuance of the war."

The practice of paroling enemy troops began thousands of years ago, at least as early as the time of Carthage. Parole allowed the prisoners' captors to avoid the burdens of having to feed and care for them while still avoiding having the prisoners rejoin their old ranks once released; it could also allow the captors to recover their own men in a prisoner exchange. Hugo Grotius, an early international lawyer, favorably discussed prisoner of war parole. During the American Civil War, both the Dix–Hill Cartel and the Lieber Code set out rules regarding prisoner of war parole. Francis Lieber's thoughts on parole later reappeared in the Declaration of Brussels of 1874, the Hague Convention, and the Geneva Convention Relative to the Treatment of Prisoners of War.

Alexander Maconochie, a Scottish geographer and captain in the Royal Navy, introduced the modern idea of parole when, in 1840, he was appointed superintendent of the British penal colonies in Norfolk Island, Australia. He developed a plan to prepare them for eventual return to society that involved three grades. The first two consisted of promotions earned through good behaviour, labour, and study. The third grade in the system involved conditional liberty outside of prison while obeying rules. A violation would return them to prison and they would start all over again through the ranks of the three-grade process. He reformed its ticket of leave system, instituting what many consider to be the world's first parole system. Prisoners served indeterminate sentences from which they could be released early if they showed evidence of rehabilitation through participation in a graded classification system based on a unit of exchange called a mark. Prisoners earned marks through good behavior, lost them through bad behavior, and could spend them on passage to higher classification statuses ultimately conveying freedom.

In an instance of multiple discovery, in 1846, Arnould Bonneville de Marsangy proposed the idea of parole (which he termed "preparatory liberations") to the Civil Tribunal at Reims.

In general, in Canada, prisoners are eligible to apply for full parole after serving one-third of their sentences. Prisoners are also eligible to apply for day parole, and can do this before being eligible to apply for full parole.

Any prisoner whose sentence is less than two years is sent to a correctional facility in the province or territory where they were convicted, whilst anyone sentenced to serve no less than two years will be sent to a federal correctional facility and will thus have to deal with the Parole Board of Canada.