Realistic conflict theory (initialized RCT), also known as realistic group conflict theory (initialized RGCT), is a social psychological model of intergroup conflict. The theory explains how intergroup hostility can arise as a result of conflicting goals and competition over limited resources, and it also offers an explanation for the feelings of prejudice and discrimination toward the outgroup that accompany the intergroup hostility. Groups may be in competition for a real or perceived scarcity of resources such as money, political power, military protection, or social status. Feelings of resentment can arise in the situation that the groups see the competition over resources as having a zero-sums fate, in which only one group is the winner (obtained the needed or wanted resources) and the other loses (unable to obtain the limited resource due to the "winning" group achieving the limited resource first). The length and severity of the conflict is based upon the perceived value and shortage of the given resource. According to RCT, positive relations can only be restored if superordinate goals are in place.
The theory was officially named by Donald Campbell, but has been articulated by others since the middle of the 20th century. In the 1960s, this theory developed from Campbell's recognition of social psychologists' tendency to reduce all human behavior to hedonistic goals. He criticized psychologists like John Thibaut, Harold Kelley, and George Homans, who emphasized theories that place food, sex, and pain avoidance as central to all human processes. According to Campbell, hedonistic assumptions do not adequately explain intergroup relations. Campbell believed that these social exchange theorists oversimplified human behavior by likening interpersonal interaction to animal behavior. Similar to the ideas of Campbell, other researchers also began recognizing a problem in the psychological understanding of intergroup behavior. These researchers noted that prior to Campbell, social exchange theorists ignored the essence of social psychology and the importance of interchanges between groups. To the contrary of prior theories, RCT takes into account the sources of conflict between groups, which include, incompatible goals and competition over limited resources.