This study is designed to investigate the extent and the development of students’ self- regulated learning (SRL) on the upper secondary school level. The results are based on a survey of students in grade 10 and 11 at the beginning and at the end of one school year. Statistical analyses based on difference score models revealed that the students’ strategy use did partially develop over the course of a school year. However, this was not the case for the students’ metacognitive strategy knowledge. Students’ strategy use and metacognitive strategy knowledge are on a moderate level. Furthermore, cluster analysis on the basis of inter-individual differences in SRL revealed four different types of learners that differed from each other regarding their marks in the academic subject of German. Structural equation modelling showed differences in students’ metacognitive strategy knowledge according to gender and educational family background. In addition, statistical analyses based on multi- level analyses revealed that individual perception of social integration had a positive effect on students’ metacognitive strategy knowledge. In contrast, students in classes with more self-reflexive arrangements tended to exhibit a lower level and negative development of metacognitive strategy knowledge. In summary, there is still a lot of potential to foster SRL on the upper secondary school level. Theoretical and practical implications of these findings are discussed.