There is growing interested in the role of psychological resilience in shaping adolescent students' delinquent behaviours in secondary schools. In this article, using locus of control theory, we examine the role of psychological resilience in terms of hardiness, resourcefulness, and optimism in minimizing the occurrence of cyber delinquent behaviours of secondary school students in Saudi Arabia. We introduce optimism and resourcefulness as protective factors critical for adolescents engaging in cyber delinquent behaviour and conceptualize them as characteristics of individuals with an internal locus of control. This study examines the multiple mediation effects of optimism and resourcefulness in the relationship between hardiness and cyber delinquent behaviours. The structural equation modelling results confirm eight hypotheses and that optimism and resourcefulness mediate the relationship between hardiness and cyber delinquent behaviours. These findings demonstrate the multiple mediation effects of optimism and resourcefulness and the important role of hardiness, resourcefulness, and optimism in predicting cyber delinquent behaviour. We draw implications for theory, secondary schools, and policymakers.