This paper investigates the associations between fertility decline in Western Europe since the nineteenth century and the most elementary institution through which relationships between kin are defined: the family. Fertility levels in Western Europe declined strongly since the mid-nineteenth century but also show marked regional variations, comparable to developments in sub-Saharan Africa in the world today. Recent explanations of fertility decline point at the role of social relationships with kin and non-kin in the diffusion of family limitation. Based on the classification of family systems by Emmanuel Todd, theoretical connections between family systems and the level and speed of fertility change are made. Non-authoritarian family systems are expected to be more open towards change since non-kin are more likely to enter the social network. Authoritarian family systems on the other hand are expected to maintain higher levels of fertility due to the dense kinship networks. The findings in this paper show no clear association between family systems and reproductive outcomes during the course of the demographic transition. Fertility outcomes are more strongly associated with past fertility levels and the level of fertility in neighbouring regions.