The relevance of institutional arrangements concerning the German school system for social inequalities remains comparatively unclear, due to the prevalent use of only simple and mostly static categories. The present study adds to this debate and analyses the effect of different regulations at the transition to upper secondary schools on educational achievement and social inequality. Duration of primary schooling and tracking recommendations are taken into account. Empirical analyses are based on information of the related Education Acts (1985–2010) as well as data from the German Socio-Economic Panel Study (SOEP). This approach constitutes a significant advancement as it allows for an overall identification of changes in the institutional features between and within states. Results indicate that children who attend primary schools that cover six instead of four years are more likely to be enrolled in an academic-track Gymnasium. These effects are especially strong for children with lower social background. There is no significant difference between secondary school systems with overall pure early tracking and school systems with fewer school tracks and delayed tracking in the sense that only students who don’t attend upper secondary school aren’t tracked after the fourth grade. Furthermore, the results reveal that the relative importance of (mandatory) track recommendations tends to be lower for children of parents with higher socioeconomic status, even if children in general are more likely to attend the Gymnasium at age 15, when the parents’ freedom of choice isn’t restricted by teachers’ recommendations.