This paper documents the wide variation in living arrangements experienced by children in developing regions using data from 19 Demographic and Health Surveys. Traditionally, researchers and policymakers concerned with child welfare have assumed that, apart from exceptional cases, children live with their mothers, experience childhood together with their siblings, and have access to resources from both biological parents. Data presented in this paper contradict this assumption. The data demonstrate that, in many countries of sub-Saharan Africa and Latin America as opposed to parts of Asia and North Africa, children spend substantial proportions of their childhood years apart from one or both parents and, by extension, apart from at least some of their siblings. The mothers of many of these children do not live with a partner or are in marital circumstances that may attenuate the link between the child and the father. In countries where child fostering is practiced, the likelihood that children will live apart from their mothers is negatively related to their mother's access to the resources of their fathers and other relatives and positively related to the number of younger siblings. The focus of the paper is on four essential elements of children's living arrangements that influence their access to resources: (1) mother-child co-residence, (2) father-child co-residence, (3) household structure and (4) the number, presence and spacing of siblings. The research suggests that significant proportions of young children, particularly in sub-Saharan Africa, benefit from the support provided by family members other than their parents. This support, which involves the co-residence of family members beyond the nuclear unit, can take many forms: the co-residence of three generations within the same household, the inclusion of a single mother and her children as a sub-family within a more complex household, or the exchange of children between kin. Surprisingly, despite enormous variations between countries in current fertility rates (ranging from roughly 2 to 7 births per woman), children in countries as diverse as Thailand and Mali spend their childhood with no more than 2 to 3 children on average sharing the same household. Thus, childhood as it is experienced in many parts of the developing world has much that is common despite apparent differences and much else that is different despite apparent similarities.