We analyse the utility of social capital for children's achievement, and if this utility interacts with family human capital and the quality of the parent-child relationship. Our focus is on parental activities directly related to children's school work. Our data stem from a Swedish cohort born in 1953 and consist of both survey and register data. We find that parents with more human capital tended to offer their children more social capital. OLS regressions showed that, when present, social capital was directly related to children's grades and its utility for achievement did not depend on parents' human capital. The utility of social capital was enhanced when combined with a very good parent-child relation.