Abstract Based on Self-Determination theory and social interaction models of social justice, in this article we examined whether perceptions of fairness catalysed the positive effects autonomy support on motivational and well-being outcomes. The study was conducted in the context of an all-boys school with 302 students, adopting a prospective design. Using surface analysis to estimate the dependent variables to be tested in non-liner regressions, the current research empirically extends social interaction models of distributive justice by testing, for the first time, whether perceptions of fairness can moderate the effects of autonomy supportive practices on satisfaction of psychological needs. The results demonstrated that perceptions of fairness engendered positive effects of favourable forms of autonomy support on satisfaction of the psychological need for competence. No analogous positive effects on other outcomes were found. Therefore, the perceptions of fairness constitute an important component of autonomy-supportive class climates that catalyse positive effects of favourable forms of autonomy support on satisfaction of the psychological need for competence. This evidence suggests that students are more likely to experience high levels of competence during physical education classes when they perceive that their favourable treatment is fair, though the effect does not generalise to autonomous motivation or subjective well-being.