The aim of this thesis is to determine the level of development of social-emotional competences of students of secondary schools in Zagreb, based on the model of social-emotional learning developed by CASEL, with regard to gender and chosen educational, i.e. high school or vocational high school program. Social- emotional learning is defined as a process that affects the acquisition and effective application of knowledge, attitudes and skills necessary for understanding and managing feelings towards oneself and others, setting and achieving desired goals, maintaining positive relationships and making responsible decisions in children, adolescents, but also in adults. The research was carried out as part of the evaluation of the school preventive program Skills for Action in Croatian secondary schools, and this program was carried out in cooperation with the Agency for Education and the United Nations Office on Drugs and Crime. The participants of this study were students (n = 265) from selected first grades of two high schools and two vocational high schools (three grades per school). The research established the need for a more consistent and better implementation of school preventive programs that would result in an increase in the development of social-emotional competences among students, because at least a third of the examined students do not demonstrate appropriate social-emotional competences in socially challenging situations. It has been shown that male students are at greater risk of choosing violent and delinquent behavior compared to female students, and that students of vocational schools have less developed social-emotional competences compared to high school students.