Studies of diffusion have a long-standing history within the social sciences. Recent concurrent political uprisings within the mid-East and the global spread of the Occupy! Movement have renewed focus on the spread of tactics within and between social movements organizations. The article discusses the historical context of diffusion research, with an emphasis on diffusion research within the study of social movements. The author calls for continued research on the spread of tactics within international social movements given that such movements are currently dynamic and contested sites of struggle.