We introduce the construct of network inertia, referring to a persistent organizational resistance to changing interorganizational network ties or difficulties that an organization faces when it attempts to dissolve old relationships and form new network ties. Previous research has neglected the process of network change in favor of an emphasis on identifying beneficial content effects of networks. We emphasize the constraints on network change and propose a multilevel conceptual model relating key sources of network inertia to changes in network ties. We also discuss the implications of network inertia for the evolution of networks.