In this study we look the relationship between students’ mathematical competencies and their relationship to family background variables. The backdrop of this investigation is a follow-up measurement to the 2012 Programme for Internationas Student Assessment (PISA) in 2013. The large influence of family variables for student achievement in Germany has been the result of numerous studies. Yet, in more recent analyses trend developments in the context of PISA show improvement in this area. This circumstance provides evidence for the need of a longitudinal investigation of family background variables and their relationship with students’ mathematical competence. Multilevel analyses stress the great importance of prior competencies and support prior research indicating that much of the achievement differences due to migration status come down to differences in financial resources. Controlling for class composition had only limited effects, but decreased the role of migration status even further. Results are discussed in light of recent research.