This chapter discusses some of unique differences as they relate to the assessment, diagnosis, and treatment in military counseling and related services. It addresses some of salient issues for professional counselors who must assess, diagnose, and treat active duty and veterans. Overall, understanding psychosocial adjustment issues related to chronic illness and disability as well as working with clients that have psychiatric, substance abuse, and mental health issues are essential in healing traumatic experiences. The chapter assists professionals in building a rapport with the intent of establishing a strong working alliance within the military culture. It provides an excellent and comprehensive resource for helping professional counselors understand the difficult challenges that military personnel must navigate during various stages of their deployment cycle. A great deal of counselor education and research has been developed that focuses on preparing professional counselors in understanding the unique cultural attributes of a diversity of cultural groups.