Although ethical decision making is a key concern of organizations, the impacts of IT on ethical discourse is an underexplored topic. The laboratory experiment reported in this paper examines the impacts of the use of group support systems (GSSs) on moral discourse. Drawing upon Toulmin’s (1958) model of argumentation and Kohlberg’s (1976) framework of stages of moral reasoning, we used the technique of argumentation mapping (Fletcher and Huff 1990) to analyze group discussions of scenarios involving music piracy and hacktivism (computer hacking for a social cause) by GSS-supported and face-to-face groups. The results indicate that use of GSS can have a significant impact on the extent and diversity of the argumentation contributed during group discussion involving ethical dilemmas, including the number of grounds and rebuttals and the number of unique stages of moral reasoning underpinning the argumentation.