In the Croatian scientific and research area it is noticible a limited number of researches on the quality of school life. Leonard (2002) defines the phenomenon of the quality of school life as a set of positive and negative affective experiences resulting from all educational school experiences. Researches on the quality of school life is extremely useful for all participants of the educational system because they can improve certain aspects of the educational system. Also, Ferdosipour & Mousavi (2020) point out that the quality of school life affects on general life satisfaction and is reflected in other areas of life. There are numerous factors that influence on the quality of school life, and some of them are: class teaching atmosphere (Mok & Flynn 2002), educational experiences of student during the teaching process in the classroom (Kong, 2008), interpersonal relationships of individuals which make school enviroment (Ferdosipur & Mousavi, 2020) and some individual student characteristics such as the development of social competence (Fejzić, 2017). Modern times social competence presents as one of the most important life competences which is aimed at the personal and professional growth o fan individual. The importance of the development of certain aspects of social competence is even more expressed in the period of adolescence, when interpersonal relationships with peers are extremely important for cognitive, social and emotional development. The aim of this research was to examine how adolescents observe their own social competences, the quality of friendship and the quality of school life, and to what extent social competences and the quality of friendship contribute to the explanation of the quality of school life. Empirical quantitative research method was used in the research and the dana was collected using paper-pencil method. A total of 1009 sixth, seventh and eighth grade students from 14 elementary schools in the City of Zagreb and Zagreb County participated in the research. As the research participants are students from sixth to eight grade of elementary school, all stages of the research took place in accordance with the guidelines of the Ethical Standards for Research with Children (2020) and with the prior consent of parents/guardians. The dana was collected in the period from December 12, 2022 to May 9, 2023, exclusively during Headroom teacher class with prior agreement with Headroom teachers of individual classes. Social demographic characteristics of the participants included gender, grade, age, final grades of the previous school year from Croatian, Mathematics and English and information wheter and how many siblings they have. The research results showed that there is a postive connection between some specific aspects of the quality of school life (Preparation for the future, Social integration, School achievement and Teachers with both dimensions of social competence and with the quality of friendship). Furthermore, the research found that female adolescents achieved higher values on the scale of friendship quality, preparation for the future and skills of emotional regulation compared to male adolescents and a higher score on the factor of negative feelings towards school and a lower score on Social integration and Prosocial communication skills. The results also showed that the students of the sixth grade evaluate their own social competences, the quality of friendship and positive aspects of the qualiry of school life more positively than the students of the seventh and eighth grades. By seeing the results of the research we can conclude that students with better final grades in Croatian, English and Mathematics evaluate more positively their own social competence, quality of friednship, general satisfaction with school and specific domains of the quality of school life. By analyzing the research results it can be determined that students who do not have siblings manifest more unpleasant emotions related to school. The stated knowledge of this research can serve as a kind of foundation to future research on the quality of school life and as a guidelines to Holders of educational policy for building a school culture in which students will feel satisfied, successful and accepted.