Despite the well-documented effect of parent–child relations in childhood on the reproduction of social disadvantage, little is known about how relationships between parents and their grown-up children are associated with this process. The present study addresses this research gap by investigating whether structural, cognitive, and functional aspects of family social capital in adulthood are connected to the risk of relative income poverty and its intergenerational reproduction. Based on a longitudinal sample from data of the German Family Panel (pairfam), random effects regression models as well as mediation analysis (KHB method) reveal that affectual and structural facets of intergenerational relations in adulthood matter in two ways for understanding the intergenerational transmission of poverty. First, emotionally close intergenerational relations and living in proximity of the parental home in adulthood counterbalance the experience of economic deprivation in childhood by alleviating poverty risks. Second, emotionally and spatially distant relations between adult children and their parents partially mediate the social inheritance of poverty across generations and time. We additionally tested the possible moderating role of migration background but could not find considerable evidence that later-life family social capital matters differently for native and migrant families in predicting the risk of poverty.