The North Atlantic Treaty Organization (NATO) Exploratory Team meeting, "Model-Driven Paradigms for Integrated Approaches to Cyber Defense," was organized by the NATO Science and Technology Organization's (STO) Information Systems and Technology (IST) panel and conducted its meetings and electronic exchanges during 2016. This report describes the proceedings and outcomes of the team's efforts. Many of the defensive activities in the fields of cyber warfare and information assurance rely on essentially ad hoc techniques. The cyber community recognizes that comprehensive, systematic, principle-based modeling and simulation are more likely to produce long-term, lasting, reusable approaches to defensive cyber operations. A model-driven paradigm is predicated on creation and validation of mechanisms of modeling the organization whose mission is subject to assessment, the mission (or missions) itself, and the cyber-vulnerable systems that support the mission. This by any definition is a complex socio-technical system (of systems), and the level of detail of this class of problems ranges from the level of host and network events to the systems' functions up to the function of the enterprise. Solving this class of problems is of medium to high difficulty and can draw in part on advances in Systems Engineering (SE). Such model-based approaches and analysis could be used to explore multiple alternative mitigation and work-around strategies and to select the optimal course of mitigating actions. Furthermore, the model-driven paradigm applied to cyber operations is likely to benefit traditional disciplines of cyber defense such as security, vulnerability analysis, intrusion prevention, intrusion detection, analysis, forensics, attribution, and recovery.