This chapter discusses the development and evaluation of Internet-delivered cognitive behavior therapy (ICBT) in the treatment of emotional and behavior disorders in children and adolescents. Although most evaluations of ICBT to date have focused on adults, the literature regarding its use with young people is rapidly expanding. Results thus far have been strongly encouraging, with many studies showing positive outcomes in terms of reduction in symptoms associated with a broad range of psychological disorders and in enhancing emotional well-being and psychosocial functioning. However, the research is still in its early stages and it is difficult to draw firm conclusions regarding the effectiveness of ICBT with young people. The wide variation in the way that ICBT is used also makes it hard to identify the most effective formats for treatment delivery, particularly in terms of level of therapist involvement, parent participation, group online interactivity, and type of Internet material. Despite these reservations, the evidence to date provides a strong case for continued research into the development and evaluation of ICBT approaches with young people in order to determine the most effective approaches. What is clear, however, is that young people find ICBT a very appropriate method of intervention. Nevertheless, one of the big challenges is to find methods of enhancing client engagement, motivation, and compliance with the therapy content.