This chapter examines how ethical issues are approached differently by two prominent psychological associations, how they are encountered by psychologists, the formal complaints they give rise to, and how they can be approached systematically to avoid missteps. Included are basic assumptions about ethics; the unique approaches to developing a ethics code taken by the American Psychological Association (APA) and the Canadian Psychological Association (CPA), and what each of these two codes provides; empirical data about what ethical problems psychologists encounter and what formal complaints they face; four major sets of ethical issues that are particularly complex and challenging (confidentiality, informed consent, competence, and boundaries); an area of major controversy (clinical psychology and national security); steps in ethical decision-making; and four possible lines of future research.