This thesis addresses problematic internet use among children and adolescents, a topic that is becoming increasingly relevant given the growing presence of the internet in everyday life. While the internet has significantly improved communication and access to information, its use can become problematic, especially among the younger population. The aim of this thesis is to systematize scientific knowledge on this phenomenon through a review of relevant literature. Special emphasis is placed on defining current terminology and presenting the three most common forms of problematic internet use among children and adolescents. The thesis also discusses the challenges in diagnosing problematic internet use due to a lack of consensus among researchers regarding the validity of diagnostic criteria. It presents some of the most used measurement instruments, as well as prevalence rates and correlates of problematic internet use. Furthermore, the thesis explores the negative consequences that excessive internet use can have on the educational, social, psychological, and physical functioning of children and adolescents. In the final part, the importance of the role of social pedagogues in the prevention and treatment of problematic internet use is highlighted.