Abstract. In this chapter, we propose an ethical framework for serious game design, which we term the Ecosystem for Designing Games Ethically (EDGE). EDGE expands on Zagal's categorization of ethical areas in game design by incorporating the different contexts of design and their use. In addition, we leverage these contexts to suggest four guidelines that support Ethical Stewardship in serious game design. We conclude by discussing a number of specific areas in which ethics plays a role in serious game design. These include games in (a) a military context, (b) the consideration of privacy issues, and (c) the evaluation of game design choices.