This is the secondary school module (Waves 4, 5, 6, and 7) of The Arnhem School Study (TASS). The secondary school module of TASS builds on a study among primary schools. The data for the primary school sample of TASS (Wave 1-3) were collected at 26 different primary schools in the city of Arnhem, in the Netherlands. Respondents included students attending the last 3 years of primary education (age 10-12). Consequently, the secondary school module of TASS starts with Wave 4. The goal of the secondary school module was to capture an entire cohort of students in the city after their transition from primary to secondary school. The data collection for the secondary sample of TASS (Wave 4-7) took place among students (age 12-13 at the first wave) attending one of the 12 secondary schools in Arnhem. Sixty-one classes (88.4% of all first-year classes in secondary schools in Arnhem) took part in the study. Since all schools were located within the same city, TASS is not a random sample. However, almost all schools in Arnhem participated, meaning that schools did not self-select into the sample.