This paper describes a framework for ethical analysis of the practice of computer Modeling & Simulation (M&S). Each of the authors presents a computational model as a case study and offers an ethical analysis by applying the philosophical, scientific, and practical components of the framework. Each author also provides a constructive response to the other case studies. The paper concludes with a summary of guidelines for using this ethical framework when preparing, executing, and analyzing M&S activities. Our hope is that this collaborative engagement will encourage others to join a rich and ongoing conversation about the ethics of M&S.