Training for and engaging in military operations is physically and psychologically demanding. Identification of service members who are at risk for, or are experiencing, psychological problems is the key to maximizing their mental health and advancing the military mission. In contrast to problems, psychological knowledge can also enhance resilience, strength, and performance. Psychological and neuropsychological evaluation and treatment of military personnel promote the well-being of service members and enhance military readiness. However, a variety of ethical issues must be considered for psychological services to be effective. Psychologists benefit from anticipating the ethical issues and challenges, striving to avoid ethical dilemmas, addressing ethical dilemmas when they occur, and aspiring to high standards of ethical practice. A structured, systematic approach to ethical decision-making facilitates good ethical solutions and outcomes. The goals of the present chapter are to describe the relevant ethical considerations in military psychology and provide clinicians with a structured approach to ethical decision-making. Because the manner in which mental health professionals practice with military personnel differs both within and among countries, an attempt is made to cover issues that are relevant broadly, with the expectation that practitioners will be able to apply general principles to their specific contexts.