The purpose of the study has been to examine school social workers´ professional practice in order to create an understanding of the opportunities and obstacles that exist for school social workers in their work against cyberbullying. This study has been based on a qualitative method where eight semi-structured interviews with school social workers from different municipalities in Sweden. The empirical data has been analyzed on the basis of previous research and the theoretical framework: professional theory and discretion. The results show that the school social worker´s professional role is characterized by overall job descriptions and a responsibility for adolesecents´ well-being. Cyberbullying appears to be complex and difficult to access, while at the same time it is important to prevent. The school social worker pursues prevention through collaboration with teachers and guardians and through class exercises. Factors that affect the school social worker's opportunities to work preventively are time and school management.