In geography, the spatial dimension of networks has long been taken for granted. This is not the case in natural sciences, of which physics distinguishes between spatial and nonspatial relationships. The core element at stake is thus distance, resulting in time and cost to travel the network and/or to create new links and nodes. Yet in many disciplines, spatial networks remain analyzed in a binary fashion, without taking into account the length of links and the local characteristics of nodes. This entry reviews how the spatial dimension of networks is addressed in the geographic literature and in other sciences, leading to the conclusion that there is a need for further research in this field.