This study aimed to identify determinants of interdependent happiness (IH), with a focus on social capital resources. Using data from a population survey conducted in Sapporo, Japan, we ran hierarchical regressions to compare determinants of IH with determinants of a standard measure of subjective well-being (SWB), the Satisfaction With Life Scale (SWLS). While we confirmed the relationships of control variables generally associated with SWB also for IH, we found several decisive differences between the two well-being measures regarding social capital. For IH, an overall larger share of variance was predicted by social capital resources than for SWLS. IH is most strongly affected by social affiliation, which measures a sense of belonging to society, followed by interpersonal reliance, and social support. Reciprocal norms and institutional reliance predicted only IH, but not SWLS. Overall, our results imply that IH captures aspects of well-being related to social capital not fully covered by standard measures of SWB. Thus, for societies in which the cultural construal of happiness is more inclined to IH, the specific importance of social capital resources for SWB might be underestimated when relying solely on standard measures of well-being.