A pension is a fixed sum to be paid regularly to a person, typically following retirement from service. There are many different types of pensions, including defined benefit plans, as well as several others. Pensions should not be confused with severance pay; the former is paid in regular installments, while the latter is paid in one lump sum.

The terms retirement plan and superannuation tend to refer to a pension granted upon retirement of the individual.Retirement plans may be set up by employers, insurance companies, the government or other institutions such as employer associations or trade unions. Called retirement plans in the United States, they are commonly known as pension schemes in the United Kingdom and Ireland and superannuation plans (or super) in Australia and New Zealand. Retirement pensions are typically in the form of a guaranteed life annuity, thus insuring against the risk of longevity.

A pension created by an employer for the benefit of an employee is commonly referred to as an occupational or employer pension. Labor unions, the government, or other organizations may also fund pensions. Occupational pensions are a form of deferred compensation, usually advantageous to employee and employer for tax reasons. Many pensions also contain an additional insurance aspect, since they often will pay benefits to survivors or disabled beneficiaries. Other vehicles (certain lottery payouts, for example, or an annuity) may provide a similar stream of payments.

The common use of the term pension is to describe the payments a person receives upon retirement, usually under pre-determined legal or contractual terms. A recipient of a retirement pension is known as a pensioner or retiree.