Life imprisonment (also known as imprisonment for life, life in prison, whole-life tariff,^[1] a life sentence, a life term, lifelong incarceration, life incarceration or simply life) is any sentence of imprisonment for a crime under which convicted persons are to remain in prison either for the rest of their natural life or until paroled or otherwise commuted to a fixed term. Crimes for which, in some countries, a person could receive this sentence include murder, attempted murder, conspiracy to commit murder, blasphemy,^[2] apostasy, terrorism, severe child abuse, rape, child rape, espionage, treason, high treason, drug dealing, drug trafficking, drug possession, human trafficking, severe cases of fraud, severe cases of financial crimes, aggravated criminal damage in English law, and aggravated cases of arson, kidnapping, burglary, or robbery which result in death or grievous bodily harm, piracy, aircraft hijacking, and in certain cases genocide, ethnic cleansing, crimes against humanity, certain war crimes or any three felonies in case of three strikes law. Life imprisonment (as a maximum term) can also be imposed, in certain countries, for traffic offenses causing death.^[3] The life sentence does not exist in all countries: Portugal was the first to abolish life imprisonment, in 1884.

Where life imprisonment is a possible sentence, there may also exist formal mechanisms for requesting parole after a certain period of prison time. This means that a convict could be entitled to spend the rest of the sentence (until that individual dies) outside prison. Early release is usually conditional on past and future conduct, possibly with certain restrictions or obligations. In contrast, when a fixed term of imprisonment has ended, the convict is free. The length of time served and the conditions surrounding parole vary. Being eligible for parole does not necessarily ensure that parole will be granted. In some countries, including Sweden, parole does not exist but a life sentence may - after a successful application - be commuted to a fixed-term sentence, after which the culprit is released as if the sentence served was that originally imposed.

In many countries around the world, particularly in the Commonwealth, courts have the authority to pass prison terms which may amount to de facto life imprisonment.^[4] For example, courts in South Africa have handed out at least two sentences that have exceeded a century, while in Tasmania, Australia, Martin Bryant, the perpetrator of the Port Arthur massacre in 1996, received 35 life sentences plus 1,035 years without parole, while Aurora Cinema shooter James Holmes received 12 consecutive life sentences plus 3,318 years without the possibility of parole for killing 12 and injuring 70 in a shooting spree and booby trapping his apartment with explosives. Sentence without parole effectively means a sentence can not be suspended; the prisoner may, however, effectively in any particular case released following a pardon, either on appeal, retrial or on humanitarian grounds, such as imminent death. In several countries where ‘’de facto’’ life terms are used this is commonplace, such as in the case of Abdelbaset al-Megrahi.

Few countries allow for a minor to be given a lifetime sentence with no provision for eventual release; these include Antigua and Barbuda, Argentina (only over the age of 16),^[5] Australia, Belize, Brunei, Cuba, Dominica, Saint Vincent and the Grenadines, the Solomon Islands, Sri Lanka, and the United States.

According to a University of San Francisco Law School study, only the U.S. had minors serving such sentences in 2008.^[6] In 2009, Human Rights Watch estimated that there were 2,589 youth offenders serving life sentences without the possibility for parole in the U.S.^[7][8] The United States leads in life sentences (both adults and minors), at a rate of 50 people per 100,000 (1 out of 2,000) residents imprisoned for life.^[9]

In 2011, the Supreme Court of the United States ruled that sentencing minors to life without parole, automatically (as the result of a statute) or as the result of a judicial decision, for crimes other than intentional homicide, violated the Eighth Amendment's ban on "cruel and unusual punishments", in the case of Graham v. Florida.^[10]

Graham v. Florida was a significant case in juvenile justice. In Jacksonville, Florida, Terrence J. Graham tried to rob a restaurant along with three adolescent accomplices. During the robbery, one of Graham's accomplices had a metal bar that he used to hit the restaurant manager twice in the head. Once arrested, Graham was charged with attempted armed robbery and armed burglary with assault/battery. The maximum sentence he faced from these charges was life without the possibility of parole, and the prosecutor wanted to charge him as an adult. During the trial, Graham pleaded guilty to the charges, resulting in three years of probation, one year of which had to be served in jail. Since he had been awaiting trial in jail, he already served six months and therefore was released after six additional months.^[11]

Within six months of his release, Graham was involved in another robbery. Since he violated the conditions of his probation, his probation officer reported to the trial court about his probation violations a few weeks before Graham turned 18 years old. It was a different judge presiding over his trial for the probation violations a year later. While Graham denied any involvement of the robbery, he did admit to fleeing from the police. The trial court found that Graham violated his probation by "committing a home invasion robbery, possessing a firearm, and associating with persons engaged in criminal activity",^[11] and sentenced him to 15 years for the attempted armed robbery plus life imprisonment for the armed burglary. The life sentence Graham received meant he had a life sentence without the possibility of parole, "because Florida abolished their parole system in 2003".^[11]

Graham's case was presented to the United States Supreme Court, with the question of whether juveniles should receive life without the possibility of parole in non-homicide cases. The Justices eventually ruled that such a sentence violated the juvenile's 8th Amendment rights, protecting them from punishments that are disproportionate to the crime committed,^[11] resulting in the abolition of life sentences without the possibility of parole in non-homicide cases for juveniles.

In 2012 the Supreme Court ruled in the case of Miller v. Alabama in a 5–4 decision and with the majority opinion written by Associate Justice Elena Kagan that mandatory sentences of life in prison without parole for juvenile offenders are unconstitutional. The majority opinion stated that barring a judge for considering mitigating factors and other information, such as age, maturity, and family and home environment violated the Eighth Amendment ban on cruel and unusual punishment. Sentences of life in prison without parole can still be given to juveniles for aggravated first-degree murder, as long as the judge considers the circumstances of the case.^[12][13]

In a number of countries, life imprisonment has been effectively abolished. Many of the countries whose governments have abolished both life imprisonment and indefinite imprisonment have been culturally influenced or colonized by Spain or Portugal and have written such prohibitions into their current constitutional laws (including Portugal itself but not Spain).

A number of European countries have abolished all forms of indefinite imprisonment, including Serbia, Croatia and Spain, which set the maximum sentence at 40 years (for each conviction, which in practice keeps the possibility of de facto life imprisonment), Bosnia and Herzegovina, which sets the maximum sentence at 45 years, and Portugal, which abolished all forms of life imprisonment with the prison reforms of Sampaio e Melo in 1884 and sets the maximum sentence at 25 years.

Norway (de jure) and Spain (de facto from 1993 until February 2018, the question being now debated of reintroducing de jure life imprisonment, its habitual practice before it became a democracy in 1978-1983) have abolished life imprisonment but retain other forms of indefinite imprisonment.

In Europe, there are many countries where the law expressly provides for life sentences without the possibility of parole. These countries are England and Wales (within the United Kingdom), the Netherlands, Moldova, Bulgaria^[15], Italy, Hungary, Austria, Malta, Albania, and the Republic of Ireland.

In Sweden, although the law does not expressly provide for life without the possibility of release, some convicted persons may never be released, on the grounds that they are too dangerous. In Italy, persons that refuse to cooperate with authorities and are sentenced for mafia activities or terrorism are ineligible for parole and thus will spend the rest of their lives in prison. In Austria, life imprisonment will mean imprisonment for the remainder of the offender's life if clemency is rejected by the President of Austria, and in Malta, there is never any possibility of parole for any person sentenced to life imprisonment, and any form of release from a life sentence is only possible by clemency granted by the President of Malta. In France, while the law does not expressly provide for life imprisonment without any possibility of parole, a court can rule in exceptionally serious circumstances that convicts are ineligible for parole if convicted of child murder involving rape or torture, premeditated murder of a state official or terrorism resulting in death. In Moldova, there is never a possibility of parole for anyone sentenced to life imprisonment, as life imprisonment is defined as “deprivation of liberty of the convict for the entire rest of his/her life”. Where mercy is granted in relation to a person serving life imprisonment, imprisonment thereof must not be less than 30 years. In Albania, no person sentenced to life imprisonment is eligible for parole; this effectively means imprisonment for the natural life of the convicted person, unless the prisoner is found not likely to re-offend and has displayed good behavior, and the convicted person has served at least 25 years. Also, in the Netherlands, there is never a possibility of parole for any person sentenced to life imprisonment, and any form of release for life convicted in the country is only possible when granted royal decree by the King of the Netherlands. In Europe, only the Netherlands, Moldova and Malta explicitly preclude parole or any form of release for life sentences in all cases. Even in other European countries that do provide for life without parole, courts continue to retain judicial discretion to decide whether a sentence of life should include parole or not. In Albania, the decision of whether or not a life convicted person is eligible for parole is up to the prison complex after 25 years has been served, and release eligibility depends on the prospect of rehabilitation and how likely it is he or she will re offend or not.

In South and Central America, Honduras, Nicaragua, El Salvador, Costa Rica, Venezuela, Colombia, Uruguay, Bolivia, Ecuador, and the Dominican Republic have all abolished life imprisonment. The maximum sentence is 75 years in El Salvador, 60 years in Colombia, 50 years in Costa Rica and Panama, 40 years in Honduras, 25 years in Ecuador, 30 years in Nicaragua, Bolivia, Uruguay, and Venezuela, and 25 years in Paraguay. Brazil has a maximum sentence of 30 years under statutory law, but life imprisonment and capital punishment are provided by law for crimes committed during wartime (for military crimes such as treason, desertion, and mutiny) and in the Constitution.

In the United States, a 2009 report by the Sentencing Project suggested that life imprisonment without parole should be abolished in the country. U.S. law enforcement officials opposed its proposed abolition.^[16]

Pope Francis proposed the abolition of both capital punishment and life imprisonment in a meeting with representatives of the International Association of Penal Law. He also stated that life imprisonment, recently removed from the Vatican penal code, is just a variation of the death penalty.^[17]