Background: A significant number of secondary school students struggle with comprehending texts proficiently. Enhancing their reading comprehension requires knowledge about how this ability is related to various motivational and behavioural characteristics. The central aim of this study was therefore to investigate the (in)direct relationships between ninth-grade students' motivational (i.e., reading motivation and reading self-concept) and behavioural characteristics (i.e., reading strategy use, reading engagement and reading frequency) and their reading comprehension. Furthermore, differential relationships across educational tracks are investigated. Methods: A total of 2,485 ninth-grade students completed a standardised reading comprehension test and an online questionnaire to operationalise the motivational and behavioural reading variables. Data were analysed using multigroup structural equation modelling to study potential differential relationships across educational tracks (i.e., academic, technical and vocational track). Results: Motivational and behavioural characteristics were directly related to students' reading comprehension. Moreover, the relationships between motivational characteristics and reading comprehension were mediated by behavioural characteristics. As to differences across educational tracks, not all of the relationships were corroborated similarly for each track. Conclusion: Generally, the results emphasise the importance of considering the 'bigger picture', taking into account the respective contribution of both behavioural and motivational characteristics to secondary school students' reading comprehension and concurrently considering differences across educational tracks.