Noting that Germany ranks lowest among the OECD countries for educational equalities, this paper examines whether it is the tracking of children into different types of school environments at a particularly early stages of their intellectual development (at the transition from primary to secondary school) which contributes to such inequalities. The analysis is based on data taken from two surveys of learning achievement: the Third International Mathematics and Science Study and the Programme of International Student Assessment. The data consistently reveal that although ability is a key selection criterion, childrens educational achievement varies greatly within the respective school tracks to which they are allocated. Although migrants are predominately selected to lower academic school tracks, they do not face educational inequalities if their socioeconomic background and measured ability is similar to that of German nationals. Children from rural areas, pupils from lower socioeconomic backgrounds, and boys in general have a significantly lower probability of being selected to the most academic school rack even when their educational ability is similar to that of their urban and better socially placed counterparts. Since the outcome of tracking is difficult to correct and school choice shapes career options, there is a high likelihood that such educational inequalities in secondary schooling will have an impact on pupils lives and career opportunities long after they have completed compulsory education. (Contains 48 references.) (Author/KB)