This study draws on national survey data from the United States of America (USA) and the Netherlands to compare family obligations and support behaviour for middle-generation adults who have a living aged parent and adult child. Consistent with a familialism by default hypothesis based on welfare state differences, the US sample espouses stronger family obligations than the Dutch sample. Yet, the Dutch respondents are more likely to engage in family support behaviours with both the younger and older generations, contrary to a family-steps-in hypothesis. The connection between family obligations and support behaviour is also tested, revealing a stronger association in the US sample, consistent with a family-steps-in hypothesis, but only in regard to relations with ageing parents. We conclude that Dutch respondents are more likely to act on their individual preferences whereas American respondents are more influenced by general norms of obligation towards family members. The findings are discussed in terms of social policy differences between the two countries, and in light of results from comparative European studies of intergenerational relations.