Ever since the national standards for teaching and learning mathematics in Germany were published, investigation of ways to support students' acquisition of mathematical competencies has increased. Results of these studies have been of special interest in empirical educational research. In this context, several recent studies have focused on the enhancement of students' reading comprehension skills as a means of supporting students' development of subject-specific competencies. Taking into account previous research, the empirical research project FaSaF investigated to what extent students' mathematical modelling competencies can be fostered using a 15-week training in reading strategy. Treatment effects have been investigated in three conditions: EC A, integrated reading strategy training; EC B, separate reading strategy training; and EC C, no reading strategy training. Data from German secondary school students (N = 380) who were about 13 years old were analyzed. The results indicate that students who have participated in reading strategy training experience an increase in mathematical modelling competencies but that the same increase can also be observed in students who have not participated in reading strategy training. Thus, the issue of fostering the acquisition of modelling competencies using reading strategy training is still open for debate.