Reading amount is decisive for individual students' academic success as well as for the general strength of democratic societies. Still, the amount of both leisure-time and school-related reading is decreasing. To reverse this trend, more knowledge of what drives students' school reading is needed. Drawing on Self-Determination Theory (SDT), the study is based on structured interviews with 259 students in Grades 6 and 9 from 14 different schools. Descriptive statistical analyses were made to map students' perceptions of themselves as readers and their school-related reading practices and to find out what regulates students' motivation for in-class reading. Although students express a strong will to become good readers, our data indicate that students are mainly driven by controlled motivation for their school-related reading; autonomous motivation was only expressed by a minority of students in Grade 6. What would make students read more are mainly text and instruction related factors such as more interesting texts and more time allocated to reading. Our results point to a great potential for more in-class reading across the curriculum, reading sessions that need to be regularly scheduled using carefully selected texts. In line with SDT, our findings highlight the importance of fulfilling students' need for competence, relatedness, and autonomy in order for them to develop more self-determined behaviour, such as leisure-time reading -- which in turn will boost their reading self-concept.