<p>This study investigates the association between multiple dimensions of social capital and donation participation in Japan using a nationwide individual-level dataset. Two distinct forms of philanthropic behavior are distinguished: conventional charitable giving and participation in Japan’s unique Hometown Tax Donation (HTD, Furusato-Nozei) system. Social capital is measured using the Resource Generator, and principal component analysis is applied to derive multiple dimensions. Probit regression models are used to estimate the likelihood of participation, controlling for generalized trust and a range of socioeconomic characteristics. The findings reveal contrasting patterns of association across donation contexts: linking social capital is positively associated with traditional charitable giving, whereas bonding and bridging social capital show no consistent association. By contrast, HTD participation is positively associated with bonding and bridging social capital, but not with linking social capital. Furthermore, household income remains strongly associated with HTD participation, which is consistent with the institutional features of HTD as a tax-deduction-based and incentive-linked donation system. Overall, these results suggest that the association between social capital and giving is context-dependent, underscoring the role of institutional frameworks in shaping philanthropic behavior in Japan.</p>