In this article, we study the impact of the so-called non-meritocratic factors gender, immigrant origin and social origin, and the meritocratic factors ability and achievement, on timely graduation within a specific high school type. Furthermore, the possible influence of teacher assessments of students in elementary school is investigated. Although the group of graduated students contains more girls, fewer students from immigrant origin and more students of higher social origin, multivariate analyses show that only grade point average during high school significantly affects the chances of graduating. Teachers' assessments that distinguished between graduation chances of students did not affect graduation when controlled for the non-meritocratic and meritocratic factors in the multivariate model.