Adolescence is characterized by increased stress experiences which may foster severe mental health problems. Based on the vulnerability-stress model, we assume that adolescents with a vulnerable temperament or high levels of stress are most at-risk. However, predicting adolescents’mental health based solely on stressors and temperamental disposition is less sufficient to develop tools to intervene. Therefore, the first aim of the current project is to test an innovative model that predicts the development of adolescents’internalizing and externalizing problems by including a malleable mechanism, namely emotion regulation. The model will be tested in a community, with the use of a longitudinal design and state of the art measures. The second aim of the project is to evaluate the effects of a combined (Boost Camp + E-Boost) prevention program targeting emotion regulation for at-risk adolescents. Boost Camp was evaluated as a universal prevention program with the funding of the Research Foundation Flanders (Red Noses) in 2017-218. E-Boost is an e-health program which allows at risk youth to practice emotion regulation at home. Effects will be compared in adolescents between 11 and 13 years old at low and high risk for the development of mental health problems with the use of a 2-sided clustered randomized controlled trial.