["Japanese Psychological Research, EarlyView. ", "\nAbstract\nWhen resources are scarce, people often exclude/un‐include others. However, the psychological process underlying this phenomenon is unclear. We tested the mediating role of zero‐sum beliefs using vignette (Studies 1, 2, and 3) and priming (Study 4) experiments. In Studies 1, 2a, and 2b (n = 94, 206, and 508, respectively), via increased zero‐sum beliefs, resource scarcity reduced the number of new employees to be hired (Study 1), increased opposition to accepting more foreign workers (Study 2a), and strengthened support for the return of foreign workers (Study 2b). In Study 3 (n = 132), suggesting that resources are non‐zero‐sum reduced the opposition to accepting more foreign workers via decreased zero‐sum beliefs under resource scarcity. However, in Studies 1, 2a, and 3, zero‐sum beliefs only had a partial mediating role; that is, the direct effects remained. In Studies 4a and 4b (n = 232 and 583, respectively), resource scarcity priming did not affect attitudes toward accepting more foreign workers via zero‐sum beliefs. Future research directions are discussed.\n"]