Why do people view economic success as zero-sum? In seven studies (including a large, nationally representative sample of more than 90,000 respondents from 60 countries), we explore how personal relative deprivation influences zero-sum thinking-the belief that one person's gains can only be obtained at other people's expense. We find that personal relative deprivation fosters a belief that economic success is zero-sum, and that this is true regardless of participants' household income, political ideology, or subjective social class. Moreover, in a large and preregistered study, we find that the effect of personal relative deprivation on zero-sum thinking is mediated by lay perceptions of society. The more people see themselves as having been unfairly disadvantaged relative to others, the more they view the world as unjust and economic success as determined by external forces beyond one's control. In turn, these cynical views of society lead people to believe that economic success is zero-sum. We discuss the implications of these findings for research on social comparisons, the distribution of resources, and the psychological consequences of feeling personally deprived. (PsycInfo Database Record (c) 2022 APA, all rights reserved).