Using an innovative survey of protest participants and nonparticipants from five major street demonstrations in Mexico City in 2011 and 2012, this study tests the assumption that influences on protest participation vary across different types of events; namely, ritual demonstrations and reactive protests. The comparison is based on two assumptions: that these are two of the dominant forms of protest in contemporary Latin America, and that specifying the context for different types of social movement participation provides a better understanding of the individual mobilization process for groups seeking to defend their rights or gain new benefits. The comparative analyses reveal some crucial differences. Political interest and previous political experience are more influential in the decision to take part in reactive demonstrations. For ritual demonstrations, the decision to participate tends to be driven more by personal and organizational connections.