In a cross-sectional questionnaire study with N = 1658 German students, aged between 12 and 17 years (M = 14.1, SD = 0.5), we investigated the relation of students' personal belief in a just world (BJW) to their school absenteeism and functions of school refusal behavior. In accordance with recent studies which identified negative relations between students' BJW and different forms of rule-breaking behavior (e.g., bullying, cheating), we expected that students with a strong BJW would be less likely to refuse school than those with a weak BJW. Furthermore, we considered students' personal experience of teacher justice and their feelings of exclusion from school as possible mediators in this relation. We also controlled for confounding effects of gender, age, social desirability, school reluctance, and test anxiety. To test our hypotheses, we used bootstrap mediation analyses. As expected, these analyses showed that the more students endorsed personal BJW, the less likely they were to report that they refused school. The students' personal experience of teachers justice and especially their feelings of exclusion from school at least partly mediated personal BJW's relation to school refusal behavior and its functions. The observed relations mainly persisted when we controlled for gender, age, social desirability, school reluctance, and test anxiety. We discussed the adaptive functions of BJW and implications for future school research and practice.