School psychologists should be knowledgeable about ethical, legal, and professional standards for practice and must be competent in delivering services in accordance with these standards. Professional organizations such as the American Psychological Association, the International School Psychology Association (ISPA), and the National Association of School Psychologists (NASP) have created codes of ethical conduct to support best practice. Specifically, NASP’s Principles for Professional Ethics encompass “moral duties” such as nonmaleficence, fidelity, beneficence, justice, and autonomy, and they provide a framework (i.e., a code of conduct) for the application of these moral duties within the scope of professional duty (i.e., applied professional ethics). School psychologists must also be knowledgeable about public legislation, including federal and state laws, that is relevant to the practice of school psychology. Finally, they must be able to integrate and apply legal and ethical principles to their professional practice so as to make morally sound decisions. This chapter describes the nature of legal and ethical codes that govern school psychology service delivery. Moreover, it presents a model for ethical decision-making and describes its applications.