Social capital consists of resources rooted in relationships between individuals that enable and improve the achievement of individual and collective goals, including educational ones. Relationships in the family and within educational institutions are components of social capital that can help individuals of lower socio-economic status achieve high educational goals that would be more difficult to achieve without the use of such resources (Coleman, 1988; Rogošić, 2018). Consequently, social capital promotes social mobility. The correlation between social capital and school performance in the field of educational sciences has often been investigated, and the studies examining this impact are based on various social capital theories (Bourdieu 1986 and Coleman, 1988). The paper presents detailed overview of these theories as well as an overview of empirical research in which the correlation between school success and social capital was examined, with special emphasis on the findings of research conducted in the Republic of Croatia (RH). The results of the research in the Republic of Croatia are compared and the explanations of the authors on the role of social capital in the educational achievements of primary and secondary school students are analyzed. The task of the paper is to determine the extent to which studies in Croatia indicate a significant link between social capital and school performance and how the authors explain this (in)correlation. The analysis shows that social capital in large number of analysed studies (Babarović, Burušić, Šakić, 2009; Baranović, Doolan, Jugović, Puzić, Košutić, Klepač, 2015; Baranović i Rogošić, 2021; Klepač, 2016; Matković, 2009; Rogošić, 2016; Rogošić, 2017; Rogošić, 2018) is statistically significantly and positively correlated to students' educational achievements. However, in most studies, other factors (parent’s education levels and economic capital) has a more dominant influence on school success than social capital, which is in line with the Bourdieu’s theory of socio-cultural reproduction. Therefore, the contribution of social capital in achieving social mobility needs to be further examined. As resources rooted in relationships with other individuals mainly have a positive impact on school performance and contribute to reducing educational and social inequalities, efforts should be made to build the best possible relationships between pupils, teachers, parents, and the wider community.