This chapter provides an overview of the economic literature on the effectiveness of interventions aimed at improving student performance that take place within the class or school setting. We look at effects of ICT, traditional learning materials and study skills such as meta-cognition and feedback. Overall, the evidence of the effects of didactic interventions in schools and in the classroom is mixed. Effects of ICT are mostly found in developing countries and for mathematics, whereas effects of traditional learning methods are mixed and mostly seem to depend on the teacher. Effects of interventions on study skills are mostly positive, although causal claims are questionable for most studies, except for some experimental studies on the effect of using digital testing and feedback as information providing instruments. For all the interventions discussed in this chapter it holds that the design of the intervention is of large importance to the effect that is (not) found.