Although school absenteeism trajectories can be studied through various parameters and dimensions, such as the amount of school absenteeism, sequence, and timing, most studies have only focused on changes in the amount of school absenteeism. However, when investigating the nature of school absenteeism, an analysis cannot be restricted to just changes in the amount of school absenteeism. In this article, I show how applying optimal matching on time-stamped half days of missed school (n = 6260) enables researchers, policy makers, and school professionals to uncover socio-temporal regularities in trajectories of non-attendance (i.e., the degree to which groups of pupils are absent at the same time and in the same rhythm within a given school year). Results indicated that students fall into five types of trajectories, and that these are highly predictive of student's examination results at the end of the school year. In the Discussion, I elaborate on the implications of these findings.