The primary focus of the Resistance Operating Concept (ROC) is developing a nationally authorized, organized resistance capability prior to an invasion and full or partial occupation resulting in a loss of territory and sovereignty. Resistance, as a form of warfare, can be conceived as part of a layered, in-depth national defense. Toward this end, the ROC first seeks to delineate the concept of national resilience in a pre-crisis environment. Second, the ROC seeks to develop resistance requirements, and support planning and operations in the event that an adversary compromises or violates the sovereignty and independence of an allied or partner nation. The ROC attempts to demonstrate both the significance of national resilience and the criticality of maintaining legitimacy during the conduct of resistance operations during the struggle to restore and resume national sovereignty. This publication will serve as a cornerstone of knowledge for strategists, policymakers, researchers, academics, and practitioners involved in furthering resistance capabilities.