In the Nijmegen School Study (TNSS) data is collected on bullying behavior, friendships, explicit prejudice, implicit prejudice, negative and positive forms of inter-ethnic contact, sexual harassment and gender explicit and implicit bias. The respondents of the first wave (TNSS wave 2010) are first and second year students in all levels of secondary education, within the same school located in a mid size city of the Netherlands. Following the bullying literature, different dimensions of bullying are distinguished (i.e. verbally, socially/relationally, physically and ethnic bullying). The data was collected assisted by computers, due to the nature of the state of the art instruments for measuring implicit biases. Several instruments were used: a main questionnaire and three Implicit Association tests for the student sample and a supplementary questionnaire for the mentors of the classes included in the study.