This article explores the role of changing memes in large systems change toward marriage equality—popularly referred to as same-sex marriage—in the United States. Using an abbreviated case history of the transformation, the article particularly explores the shifting memes or core units of culture, in this case, word phrases associated with marriage equality over time, influencing the social change process. Using both the case history and the empirical work on memes, the article identifies nine lessons to support others tackling large systems (...) change challenges. (shrink)