The study of networks has grown recently, but most existing models fail to capture the costs or loss of value of exclusion from the network. Intuitively, as a network grows in size and value, those outside the network face growing disparities. We present a new framework for modeling network exclusion, showing that costs of exclusion can be absolute, and might, at the extreme, eventually grow exponentially, regardless of underlying network structure. We find that costs of exclusion can also be spread to the “included” through several mechanisms such as parallel networks, and we also highlight how future research needs to capture the interaction of alternate or parallel networks to the network at hand. Backed by empirical evidence, this will have wide-reaching policy and design implications, particularly for the role of subsidies or direct intervention for network access and inclusion.