Analyses of social contexts are almost universal in social research. In many cases, however, they are not explicitly labelled or even recognized as such. The conceptual aspect of ‘context’ then remains implicit in the substantive research question – such as when investigating the effects of ‘social background’ as a characteristic of an individual’s parental or family context. Systematic commonalities can be found among various analyses that either implicitly or explicitly deal with social contexts and their relevance for education. This chapter presents a formal classification of relevant contexts and their effects on education, discusses common methodological issues of contextual analyses and gives a brief survey of important findings in relevant research areas – in particular, family effects, peer effects, school effects and effects that can be associated with larger socio-economic contexts and institutional systems.