Unlike behavioral skills training, cognitive skills training attempts to impart concepts that typically depend on tacit knowledge. Subject-matter experts (SMEs) often deliver cognitive training, but SMEs are expensive and in short supply, causing a training bottleneck. Recently, Hintze developed the ShadowBox method to overcome this limitation. As part of the Defense Advanced Research Projects Agency's Social Strategic Interaction Modules, Klein, Hintze, and Saab adapted the ShadowBox approach to train large numbers of trainees without relying on expert facilitators. As part of this program, we used the ShadowBox approach to train warfighters on the social cognitive skills needed to successfully manage civilian encounters without creating hostility or resentment. ShadowBox training was evaluated in two studies. Evaluation 1 provided 3 hr of nonfacilitated, paper-based training to Marines at Camp Pendleton and Camp Lejeune (N = 59), and improved performance (i.e., match to the SME rankings) by 28% compared to a control group. Evaluation 2 provided 1 hr of nonfacilitated training, administered via Android tablet, to soldiers at Fort Benning (N = 30) and improved performance by 21%. These results, both statistically significant, suggest ways to use scenario-based training to develop cognitive skills in the military.