Researchers have used social dominance, system justification, authoritarianism, and social identity theories, to understand intergroup phenomena ranging from racial categorization to political movements. The result has been a growing understanding of how particular sociopolitical motives and contexts impact intergroup relations, without a unifying perspective to integrate these insights. Using research on multiracial categorization as a case study, I review evidence supporting each theory’s predictions concerning how monoracial perceivers categorize multiracial people that combine their ingroup with an outgroup, with attention to the moderating role of perceiver group status. I find most studies in the multiracial categorization literature cannot arbitrate between theories of intergroup relations and reveal additional gaps in the literature. To advance this research area, I introduce the Sociopolitical Motive x Intergroup Threat (SMIT) Model of Intergroup Relations that 1) clarifies which sociopolitical motives interact with which intergroup threats to predict categorization and 2) highlights the role of perceiver group status. Moreover, I consider how the SMIT model can help understand phenomena beyond multiracial categorization.