Social capital is instrumental to personal well-being; yet, this relationship may differ by educational level. Using data from the European Social Survey (ESS), the present study explores the interconnection between tertiary education, social capital, and subjective well-being. Examining the nature of these relationships, we test the hypothesis that tertiary education moderates the relationship between two broad forms of social capital, social trust and social relatedness, and well-being. We predict a “trade-off” between individual human capital and interpersonal social capital, where either one or the other comes to play a dominant role. Furthermore, we test if overall levels of tertiary education at the national level change the strength of the relationship among individual-level forms of social capital and well-being. Although connected occupation and employment factors are also important, we find that tertiary education functions as a non-pecuniary moderator changing the nature of the relationship between social capital and well-being. Respondents with tertiary education have higher levels of well-being regardless of their self-reported level of social capital, and—what is more—the extent to which social trust and social relatedness are associated with well-being is weaker among this highly educated group. In contrast, respondents without tertiary education experience greater well-being enhancement through social capital, “catching up” in self-reported well-being at higher social capital levels. This study provides preliminary evidence that social factors predicting well-being differ across the educational spectrum.