Although past research demonstrates that perceived fairness leads to many benefits, it also tends to assume that fairness flows almost exclusively from justice adherence. We instead reason that when employees form fairness judgments, they consider not only the extent to which supervisors adhere to justice but also why supervisors do so. In particular, our work outlines three distinct theoretical pathways to fairness. Supervisory justice motives affect fairness judgments via supervisors’ justice rule adherence (behavioral) and via employees’ attributed motives (attributional), such that prosocial (self-interest) motives are positively (negatively) related to fairness judgments after controlling for justice. We also reason that people jointly consider supervisory motives and justice when forming fairness judgments (interactive), such that the relationship between prosocial (self-interest) motives and fairness judgments is more positive (negative) when justice is lower versus higher. We test our predictions across six studies, both survey and experimental. Our results support the three pathways for prosocial justice motives and the behavioral and attributional (but not interactive) pathways for self-interest justice motives. Our work suggests organizations trying to promote fairness should avoid inadvertently instilling a self-interest justice motive in their supervisors. (PsycInfo Database Record (c) 2022 APA, all rights reserved)