Healthy development in early childhood is a predictor of success in later life. As such, monitoring the development of young children and, where appropriate, intervening to support that development is of critical importance. However, resources available to support early childhood development are limited and must be allocated in the most efficient way possible. In this paper, we discuss the role of spatial targeting in the allocation of those resources. We compare two Australian cities, Greater Sydney and Canberra, and explore the clustering of areas of high and low developmental vulnerability. We find that while spatial targeting may be appropriate in some areas, in others, differences in the spatial clustering of developmental vulnerability may mean that other targeting strategies would be more effective.