Retirement is the withdrawal from one's position or occupation or from one's active working life. A person may also semi-retire by reducing work hours or workload.

Many people choose to retire when they are elderly or incapable of doing their job for health reasons. People may also retire when they are eligible for private or public pension benefits, although some are forced to retire when bodily conditions no longer allow the person to work any longer (by illness or accident) or as a result of legislation concerning their positions. In most countries, the idea of retirement is of recent origin, being introduced during the late-nineteenth and early-twentieth centuries. Previously, low life expectancy, lack of social security and the absence of pension arrangements meant that most workers continued to work until their death. Germany was the first country to introduce retirement benefits in 1889.

Nowadays, most developed countries have systems to provide pensions on retirement in old age, funded by employers or the state. However, only about 15% of private industry workers in the US had access to a traditional defined benefit pension plan as of March 2023.These plans, often called pensions, are increasingly rare, especially in the private sector, as most companies now offer defined contribution plans like 401(k)s instead. Public sector workers have much higher pension coverage, with about 75% participating in pension plans

In many poorer countries, there is no support for the elderly beyond that provided through the family. Today, retirement with a pension is considered a right of the worker in many societies; hard ideological, social, cultural and political battles have been fought over whether this is a right. In many Western countries, this is a right embodied in national constitutions.

An increasing number of individuals are choosing to put off this point of total retirement, by selecting to exist in the emerging state of pre-tirement.

Retirement, or the practice of leaving one's job or ceasing to work after reaching a certain age, has been around since around the 18th century. Prior to the 18th century, humans had an average life expectancy between 26 and 40 years. In consequence, only a small percentage of the population reached an age where physical impairments began to be obstacles to working. Countries began to adopt government policies on retirement during the late 19th century and the 20th century, beginning in Germany under Otto von Bismarck.

A person may retire at whatever age they please. However, a country's tax laws or state old-age pension rules usually mean that in a given country a certain age is thought of as the standard retirement age. As life expectancy increases and more and more people live to an advanced age, in many countries the retirement age at which the public pension is awarded has been increased in the 21st century, often progressively.

The standard retirement age varies from country to country but it is generally between 50 and 70 (according to latest statistics, 2011). In some countries this age is different for men and women, although this has recently been challenged in some countries (e.g., Austria), and in some countries the ages are being brought into line. The table below shows the variation in eligibility ages for public old-age benefits in the United States and many European countries, according to the OECD.