Globalization, global citizenship, and political engagement have become such buzzwords and cliches that we often lose the sense of their meaning. Global citizenship in particular is an elusive concept to operationalize. This article proposes to look at three dimensions of global citizenship: legal (rights and obligations), psychological identification with the global community, and political ones. Heeding the calls to wed traditional liberal education with the experiential learning in pursuit of developing students' global values and competencies, we devised and implemented a simulation called the "Global Summit on Sustainability," an active learning assignment we run in large, general education survey classes (Global Politics and Introduction to American Government & Politics) populated by mostly nonpolitical science majors. The total number of students involved in the summit range from 225 to 360 each semester. But how does having a Global Summit influence the development of global citizenship and its three dimensions in large general education undergraduate political science classes? By using (1) instructor observations at the summit; (2) statistical analyses of pre- and postsummit surveys; and (3) a qualitative review of students' written assignments, we find that the Global Summit influences the development of global citizenship skills. (Contains 11 notes and 9 tables.)