How do activists create cultural change? Scholars have investigated the development and maintenance of collective identities as one avenue for cultural change, but to understand how activists foster change beyond their own movements, we need to look at activists’ strategies for changing their targets’ mindsets and actions. Sociologists need to look at activists’ boundary work to understand both the wide-sweeping goals and strategies that activists enact to generate broad-based cultural changes. Using data from participant observation and interviews with animal rights activists in France and the United States, and drawing on research on ethnic boundary shifting, I show how activists used two main strategies to shift symbolic boundaries between humans and animals, as well as between companion and farm animals—(1) they blur boundaries through focusing and universalizing strategies and (2) they cross boundaries physically, discursively, and iconographically. This study contributes a new theoretical and empirical example to the cultural changes studied by scholars of social movements, and it also provides a useful counterpoint to studies of symbolic boundary construction and maintenance in the sociology of culture.