The purpose of this study was to examine the occurrence of problem behaviors in primary classrooms in the Republic of Croatia and to investigate teachers' level of concern and the support needed to address these behaviors. Approximately 8% of primary school teachers across Croatia completed a 20-item survey to indicate the occurrence of types of problem behaviors (i.e., distractibility, disobedience, aggression, delinquency) in their classrooms, separately for boys and girls. Level of concern for the problem behavior (1 = not at all to 4 = extremely) and need for support to address the misbehavior (1 = not at all to 4 = a lot of support) were also rated separately by student gender. Results indicated that teachers rated the occurrence of problem behaviors more frequently for boys than girls across all dimensions of problem behavior, with distractibility reported as the most frequently occurring problem both for boys and for girls. Teachers also reported significantly higher levels of concern and greater need of support for the behavior of boys in comparison to girls across the dimensions of distractibility, disobedience and aggression. Teachers reported significantly higher levels of concern than their need for support to address behaviors of distractibility and disobedience. Larger class size was associated with heightened levels of concern and support for a number of the problem behavior dimensions. Implications for future practice are recommended.