The present thesis focuses on the causal role of the people’s relationship to the authority in reactions to allocation decisions. A series of experiments investigating the effects of the authority’s group membership on reactions to allocation decisions are reported. In addition, psychological processes that may contribute to differences in responses to ingroup versus outgroup authorities’ decisions are examined. Because resource allocations across group boundaries may be particularly challenging for authorities, and because the psychological processes guiding reactions to outgroup authorities’ decisions have received very little attention, a primary aim is to examine the psychology of reactions to outgroup authorities’ decisions. Results demonstrate that people react more strongly to the favourability of procedures and outcomes when the authority is from an outgroup (vs. ingroup). By contrast, people generally react more strongly to the fairness of procedures when the authority is from an ingroup (vs. outgroup). Notably, direct activation of relational (ingroup) versus instrumental (outgroup) concerns produces the same response patterns as manipulating the authority’s group membership. Results further suggest that responses to outgroup authorities’ decisions in part can be explained by expectations that the authority is biased of members of his/her own group