This dissertation has two main themes. First, it studies the role of social and cultural capital in educational achievement from a comparative perspective. Second, it investigates determinants of social trust among adolescents, where the theoretical framework combines insights from both political socialization literature and social capital literature. The core of the thesis is three empirical papers. The first paper is novel in that it explores the relevance of social and cultural capital when measuring improvement in children’s educational achievement in two vastly different societies: Eastern and Western Europe shortly after communism. My explicit question is not if social and cultural capital contribute to educational outcomes, but whether this contribution is the same in different societies. In seeking the significance of the role of social and cultural capital, I used data from the Program for International Students Assessment (PISA) and Trends in International Mathematics and Science Study (TIMSS) which surveyed 50,000 eighth-grade pupils across Europe. Educational performance is measured by pupils test scores in mathematics. The second and third papers elaborate what is the second theme of this thesis: The origins of social trust among adolescents. In order to shed more light on this issue, I distinguish between two different forms of social trust: generalized trust, which indicates how much adolescents trust other people; and political trust, which indicates the extent to which they trust government-related institutions. I conducted an empirical analysis of the data set from the 1999 Civic Education Study conducted on 14-year old students across 18 countries. As a result, the second paper of this thesis examines the origins of generalized trust among the study’s sample group, whereas the third paper of this thesis explores determinants of political trust among adolescents. Both papers examine the link between socialisation processes within the family and school and their effects on the development of generalized and political trust. In addition, they utilize institutional theories on the development of social trust, and test the proposition that the quality of governmental functioning affects development of generalized and political trust of citizens.