Life imprisonment in Canada is a criminal sentence for certain offences that lasts for the offender’s life. Parole is possible, but even if paroled, the offender remains under the supervision of Corrections Canada for their lifetime, and can be returned to prison for parole violations.

A person serving a life sentence must serve for a certain length of time before becoming eligible for parole. First degree murder and high treason carry the longest period of parole ineligibility in the Criminal Code, at 25 years. Parole eligibility for second degree murder typically varies between 10 and 25 years, and is set by the sentencing judge.

A life sentence is the most severe punishment for any crime in Canada. Criminal laws are enacted by the Parliament of Canada and apply uniformly across the country.^[1]

High treason and first degree murder carry a mandatory sentence of life imprisonment with a full parole ineligibility period of 25 years. Previously, in the case of high treason or first-degree murder (where the offender had been convicted of a single murder) offenders could have their parole ineligibility period reduced to no less than 15 years under the Faint hope clause. However, that option was abolished by Parliament for offences committed after December 2, 2011, though it remains if the offence was committed before that date.^[2]

Second degree murder also carries a mandatory sentence of life imprisonment but with a parole ineligibility period of between 10 years and 25 years. Courts determine the parole ineligibility period based on the gravity of the offence.

Offences under the Criminal Code that carry a maximum penalty of life imprisonment in Canada (with a parole ineligibility period of between 7 years and 25 years) include treason, piracy, mutiny, aircraft hijacking, endangering the safety of an aircraft or an airport, endangering the safety of a ship or fixed platform, refusing to disperse after a riot proclamation, arson (disregard for human life), robbery, kidnapping, break and enter with intent, attempted murder, accessory after the fact to murder, conspiracy to commit murder, manslaughter, causing death by street racing, impaired driving causing death, causing death by criminal negligence, killing an unborn child in the act of birth, and aggravated sexual assault.

Under the Controlled Drugs and Substances Act, trafficking, exporting or production of schedule I or II substances also carries a maximum penalty of life imprisonment with a parole ineligibility period of between 7 years and 25 years.

Current sentencing practices ensure that, except in the case of murder, a life sentence is rarely imposed, even when the offender is found guilty for particularly grievous offences. One common exception is cases which involve terrorism-related conspiracies.^{[16][17] [18]}

As of 2013, 4,800 offenders were serving life sentences in Canada, though only 2,880 (around 60%) were incarcerated (the remainder being on parole). The vast majority of these offenders (about 96%) were serving their sentences for murder. "Lifers" constituted 23% of the federal offender population.^[19]

There is no guarantee that parole will be granted to an offender. If the Parole Board of Canada determines that an offender still poses a risk to society, that person may be detained in prison past the parole eligibility period.^[20] Any person released on parole from a term of life imprisonment or an indeterminate term of imprisonment must remain on parole, with conditions by the Parole Board, for the rest of the person's life. Violation of parole terms can result in the Parole Board imposing stricter conditions, or revoking the parole entirely, resulting in the person going back to prison.

While life sentences are rare in non-murder cases, the courts may apply a dangerous offender designation in cases involving serious violent or sexual offences. Such a designation may result in an indeterminate sentence with no maximum limit, but a parole review occurs after 7 years and every 2 years after that.

Despite formal parole eligibility after seven years, full parole is rare in cases where a dangerous offender is serving an indeterminate sentence as this provision is reserved for individuals assessed as likely to commit further serious violent offences. In violent non-murder cases involving repeat offenders, it is more likely to be used than a sentence of life imprisonment. As of 2012, nearly 500 inmates had a "Dangerous Offender" designation constituting about 3% of the federal offender population.^[21] Three years later, in 2015, 622 federal offenders had a Dangerous Offender designation. Of these, 586 (or some 94%) were incarcerated (representing 3.9% of the In-Custody Population) and 36 were in the community under supervision.^[22] This supervision lasts for the remainder of the offender's life.

See: Dangerous offender designation in Canada.

A young person (12 to 17) does not face a life sentence unless they are sentenced as an adult, since the maximum sentence under the Youth Criminal Justice Act is 10 years (for first-degree murder). A person can be sentenced as an adult if they were at least 14 years old at the time of the offence.^[23] The crown carries the burden of proving an adult sentence is appropriate and a presumption in favour of a youth sentence always exists, irrespective of the offenders age or the type of offence.^[24] Even if the crown does discharge its burden of proving an adult sentence is justified, the period of parole ineligibility for murder is nonetheless different for youths.

• Life imprisonment, worldwide overview