System justification theory (SJT) is a theory within social psychology that system-justifying beliefs serve a psychologically palliative function. It proposes that people have several underlying needs, which vary from individual to individual, that can be satisfied by the defense and justification of the status quo, even when the system may be disadvantageous to certain people. People have epistemic, existential, and relational needs that are met by and manifest as ideological support for the prevailing structure of social, economic, and political norms. Need for order and stability, and thus resistance to change or alternatives, for example, can be a motivator for individuals to see the status quo as good, legitimate, and even desirable.

According to system justification theory, people desire not only to hold favorable attitudes about themselves (ego-justification) and the groups to which they belong (group-justification), but also to hold positive attitudes about the overarching social structure in which they are entwined and find themselves obligated to (system-justification). This system-justifying motive sometimes produces the phenomenon known as out-group favoritism, an acceptance of inferiority among low-status groups and a positive image of relatively higher status groups. Thus, the notion that individuals are simultaneously supporters and victims of the system-instilled norms is a central idea in system justification theory. Additionally, the passive ease of supporting the current structure, when compared to the potential price (material, social, psychological) of acting out against the status quo, leads to a shared environment in which the existing social, economic, and political arrangements tend to be preferred. Alternatives to the status quo tend to be disparaged, and inequality tends to perpetuate.