The aim of the cross-sectional study was to reveal what coping strategies 8, 10- and 12-year-old Hungarian students (N?=?167) use in situations that are frustrating, either for themselves or their peers. The coping strategies in school situations were assessed by our own questionnaires. The instrument enables the investigation of the following behaviourally observable strategies: physical aggression, verbal aggression, resistance, venting/crying, avoidance, teacher-seeking, peer-seeking, following the norms and following teacher's instructions. The coping strategies were assessed by teacher-report and self-report questionnaires developed especially for this purpose. The most important finding of this study is that the occurrence of overt aggression increases with age, which is supported by the results of both the self-report and the teacher-report questionnaires. Results obtained by the self-report and teacher-report instruments correlated significantly in all three cohorts (p?<?0.05).