How do nongovernmental (NGO), international (IO), and military organizations cope with their dependencies and address their perceptual and real differences in order to coordinate their field operations? This question is addressed through the creation of a matrix grouping civilian (NGOs and IOs) and military operations into four general types: peacekeeping; disaster relief; complex humanitarian emergencies/warfare; and stabilization and reconstruction. Second, using Galbraith's information processing approach to organizational design, a range of formal coordination mechanisms that organizations use at the strategic and operational levels to help them cope with their dependencies in different field operations is identified. Third, the author underscores how communities of practice are emerging as informal mechanisms of coordination among civilian and military organizations. And finally, a framework of organizational forms that views communities of practice as an alternative to hierarchy and markets is offered. Believing communities of practice hold the most promise for coordination in the human security domain when hierarchies are politically untenable and markets lack accountability, the author concludes with implications for interorganization coordination research and practice.