The bachelor thesis Strategies oriented to support positive behavior at lower secondary school aims to present strategies that these schools use to prevent problem behavior. The theoretical part of the thesis defines the psychosocial development of an individual in the period of early adolescence, the concepts of problem behavior, class climate and the PBIS system. The research sample was created by eight respondents who teach at lower secondary school. Four respondents started implementing some elements of the PBIS system in year 2020/2021. Data for the research were collected by interviews in spring 2021 using Microsoft Teams. In our research we focused on preventive precaution and rulemaking. We found that the most common forms of preventive precaution are training course, classroom hours and correctly set rules. We found that rules have an important place in preventing problem behaviors and that all schools used strategies to support positive behavior. The research helped us to fulfil the goal. KEYWORDS problematic behavior, Positive Behavioral Interventions and Supports, preventive precaution, adolescenc
