A cross-national study with university students from Germany (n = 1135) and Turkey (n = 634) tested whether personal belief in a just world (PBJW) predicts students' life satisfaction and academic cheating. Based on the just-world theory and empirical findings in the school context, we expected university students with a stronger personal BJW to be more satisfied with their lives and cheat less than those with a weaker BJW. Further, we investigated the mediating role of justice experiences with lecturers and fellow students in these relations. Differences in PBJW directly and indirectly predicted undergraduates' life satisfaction. Students' justice experiences with peers mediated the relationship between PBJW and life satisfaction. Differences in PBJW indirectly predicted undergraduates' academic cheating. Students' justice experiences with lecturers mediated the relationship between PBJW and academic cheating. The results did not differ between German and Turkish students and persisted when we controlled for gender, start of studies, socially desirable responding, general BJW, and self-efficacy. We discussed the importance of personal BJW's adaptive functions and their relevance for international university research and practice.