Job security is the probability that an individual will keep their job; a job with a high level of security is such that a person with the job would have a small chance of losing it. Many factors threaten job security: globalization, outsourcing, downsizing, recession, and new technology, to name a few.

Basic economic theory holds that during periods of economic expansion businesses experience increased demand, which in turn necessitates investment in more capital or labor. When businesses are experiencing growth, job confidence and security typically increase. The opposite often holds true during a recession: businesses experience reduced demand and look to downsize their workforces in the short term.

Governments and individuals are both motivated to achieve higher levels of job security. Governments attempt to do this by passing laws (such as the U.S. Civil Rights Act of 1964) which make it illegal to fire employees for certain reasons. Individuals can influence their degree of job security by increasing their skills through education and experience, or by moving to a more favorable location. The official unemployment rate and employee confidence indexes are good indicators of job security in particular fields. These statistics are closely watched by economists, government officials, and banks.

Unions also strongly influence job security. Jobs that traditionally have a strong union presence such as many government jobs and jobs in education, healthcare and law enforcement are considered very secure while many non-unionized private sector jobs are generally believed to offer lower job security, although this varies by industry and country.