The use of theory-driven evaluation is an emerging practice in the military-an aspect generally unknown in the civilian evaluation community. First developed during the 1991 Gulf War and applied in both the Balkans and Afghanistan, these techniques are now being examined in the North Atlantic Treaty Organisation (NATO) as a means to evaluate the effects of military operations in complex, asymmetric conflict environments. In spite of these practices, theory-driven evaluation in the military is still in the developmental stages. This article traces the development to date of theory-driven evaluation in NATO and assesses its strengths and weaknesses in the military context. We conclude that a cross-pollination of ideas between military and civilian evaluators is urgently needed to improve the quality and effectiveness of military evaluation. F rom the development of methodologies to test the effectiveness of various educational initiatives in schools and universities in the early 20th century, the field of evaluation has evolved and grown into a discipline of study in its own right, and one that interlinks with many research disciplines including: Social science, public administration, public policy, and education. Throughout the world, it is now commonplace to find whole evaluation departments integrated with government agencies, nonprofit, nongovernmental, and international organizations. Furthermore, within each respective organization, the role of evaluation typically has a place throughout the entire policy and service delivery process, from the identification of a public need to ensuring the value and quality of final, implemented solutions (Rogers, 2007).The processes involved in planning, executing, and evaluating a military operation bear many similarities to that of planning, implementing and evaluating projects and services in civilian organizations. At the simplest level, in both civilian and military domains, a problem is identified that requires some action to be taken to alter the situation and rectify the problem. Although the idea of assessing both the progress and the impact of this action has been relatively well understood and extensively studied in civilian settings, the concept is surprisingly underdeveloped in the military domain.