Interpersonal and counseling skills are essential to Officers' ability to lead (Headquarters, Department of the Army, 2006, 2008, 2011). We developed a cognitive framework and an immersive training experience—the Immersive Naval Officer Training System (INOTS)—to help Officers learn and practice these skills (Campbell et al., 2011). INOTS includes up-front instruction about the framework, vignette-based demonstrations of its application, a role-play session with a virtual human to practice the skills, and a guided after-action review (AAR). A critical component of any training effort is the assessment process; we conducted both formative and summative assessments of INOTS. Our formative assessments comprised surveys as well as physiological sensor equipment. Data from these instruments were used to evaluate how engaging the virtual-human based practice session was. We compared these data to a gold standard: a practice session with a live human role-player. We found that the trainees took the virtual-human practice session seriously—and that interacting with the virtual human was just as engaging as was interacting with the live human role-player. Our summative assessments comprised surveys as well as behavioral measures. We used these data to evaluate learning produced by the INOTS experience. In a pretest-posttest design, we found reliable gains in the participants' understanding of and ability to apply interpersonal skills, although the limited practice with the virtual human did not provide additional immediate benefits. This paper details the development of our assessment approaches, the experimental procedures that yielded the data, and our results. We also discuss the implications of our efforts for the future design of assessments and training systems.