Working on modelling problems in school can show students how frequently mathematics is used in society and in everyday life. As a result, their motivation to learn mathematics can increase. However, there has not been any systematic investigation into whether, and how, these aims are achieved, nor is it known which aspects of modelling problems are meaningful to the students. In this chapter, we present a theoretical framework for analysing students’ personal meaningfulness of mathematics with regard to influencing factors and consequences. Furthermore, we present the results of a qualitative study with 15 students of grade 10 that show which characteristics of modelling problems and of working with modelling problems in class have a direct or an indirect influence on the students’ construction of personal meaningfulness.