The widely documented “outgroup homogeneity effect” refers to people’s tendency to view members of groups to which they do not belong (outgroups) as more similar to one another than members of their own groups (ingroups). Here, we present evidence for a novel but related phenomenon: People tend to view members of different minority groups as collectively more similar to one another than members of the majority group are to one another. Across nine studies (and four studies reported in the Supplemental Materials), we demonstrate a robust “minority-groups homogeneity effect” among participants from both majority groups (Studies 1–5) and minority groups (Studies 6–8), albeit less consistently among the latter. We provide experimental support for the role of beliefs in the common fate of minorities in driving this effect: When participants are led to believe that minority groups do not share a common fate, they no longer rate them as more similar than the majority (Study 9). These studies shed light on a broad pattern of social perception that may influence how members of different groups interact with one another and how they respond to cultural and demographic changes in society. (PsycInfo Database Record (c) 2025 APA, all rights reserved)