This chapter overviews the social psychology of intergroup relations; focusing on how cognitive and social interactive processes affect how people individually or collectively think and feel about, and interact with people who are not members of the same group as they are. Because what happens between groups affects and is affected by what happens within groups, this chapter also focuses more broadly on group processes. After describing relevant research methods, the chapter discusses personality and individual differences; authoritarianism and closed-mindedness; social dominance and system justification; conflict and cooperation between groups; frustrated goals and ambitions; social categorization and cognitive schemas of self and others; social identity and collective self-conception; group motives; intergroup emotions; attitudes, explanations and stereotypes; prejudice and discrimination; stigma, disadvantage and social deviance; crowds and riots; social protest and active minorities; collective action and social change; intergroup contact, social harmony and diversity; and leadership within and between groups.