For political party defections, see defection (politics).

A defector is a person who gives up allegiance to one country in exchange for allegiance to another. This act is usually in a manner which violates the laws of the nation from which the person is seeking to depart (as opposed to changing citizenship). For example, during the Cold War, the many people escaping across the Berlin Wall to flee from communist East Germany to the West were called defectors or, indeed, traitors.

The term has been widely used by the media in the United States to denote immigrants from Fidel Castro's Cuba; however, some conservatives object to this characterization, pointing out that the American press never referred to those who left Germany during the Third Reich era as "defectors."

In some cases, defectors remain in the country they are against, as an agent, or in many cases, a double agent. This is a common device in many thriller and spy novels, including those of Tom Clancy, especially Red Rabbit and the Cardinal of the Kremlin .

Defector is the title of a 1980 album by Steve Hackett.