Ten years after the Arab Spring there remains much that we do not understand about the role of social media in uprisings. An enthusiastic western news media was quick to label the 2009 Iranian uprising ‘The Twitter Revolution’ despite the marginal level of Twitter penetration in Iran at the time. The same news media in 2021 immediately attributed the US Capitol uprising to the proliferation of disinformation on social media, despite many additional complicated social factors. While scholars of different fields have attempted to explain the role of social media in uprisings since 2011, there is little more we understand about the role of social media in the January 2021 US Capitol uprising than the 2009 Green uprising in Iran. The objective of this project is to develop a framework for better understanding the relationship between social media and citizen decisions to participate in uprisings that persists through the many different examples we have seen since 2009. This study contributes to the literature by providing a game theoretic structure based on the strategic interdependence of individual behavior to better understand uprising activity in oppressive states and democracies. We explore the role of social media in uprisings by considering uprisings as a multi-player game, using Schelling’s (1978) critical mass game to model uprisings and consider the potential impact of social media on behavior. We then apply this model to the February 2011 revolution in Egypt and the 2009 Green Movement protests in Iran, testing it with data from in-depth interviews on participation decisions. If we understand uprisings as such a critical mass game, then we see that social media impacts behavior (and thus outcomes) if it can change either individuals’ underlying feelings and participation thresholds (i.e. the shape of the population’s participation curve), or their perception of the number of others who will join the uprising (i.e. the population’s position along the curve). We analyze data from interviews with Egyptians and Iranians about their decisions to join the protests or not to test the applicability of the critical mass model and to better understand the specific effects of social media use. We find in many ways individuals do make their participation decisions largely consistent with the critical mass model. The support for the role of social media in these decisions is less strong, but suggests it can impact participation by providing information regarding participation levels, assessing the benefits and costs of participating, and triggering emotions, sometimes changing opinions of the government.