Persecution in this article refers to persistent mistreatment of an individual or group by another group. The most common forms are religious persecution and persecution of ethnic groups.

The most common scenario is a majority group persecuting a minority group, since the reverse is usually impractical, although apartheid in South Africa is considered an exception. Majority groups, however, can inspire resentment where they are locally a minority and find themselves persecuted; a possible example of this is Harlem, New York.

There are various possible origins of persecutory behavior. For instance, a movement which is publically or implicitly identified with a minority group — such as a religion, a genetic heritage, a region, or other traditional distinction — might be successful enough to disrupt the status quo or become associated with violent acts. A reflective persecutory movement might then arise within the majority, not necessarily distinguishing between those who are and are not part of the movement. This persecution might in turn radicalize the minority group, resulting in a feedback cycle.

So-called opportunistic persecution occurs when someone exploits and stirs up an existing current of resentment to enhance his own political power. This opportunism can be applied "in reverse", as where a minority orator provokes persecution in order to unify a minority movement.

Perhaps one of the most commonly cited modern-day examples of persecution were Jews under the rule of Nazi Germany. This originated partly from a perception that Jews were simply "richer" than other people, as well as other stereotypes. This persecution developed into genocide.