The food sovereignty movement proposes a localist approach to meeting food security while delivering broader social, economic and environmental benefits. The movement is spawning multiple local projects of food sovereignty, whereby people are empowered to define their own culturally and environmentally appropriate food systems. As the number of enacted examples increases, the movement is also affecting change at national (and international) levels, with a number of countries creating national strategies or legislation for food sovereignty. We reflect on the challenges created by such scaling up within the existing food system. We propose a focus on issues of institutional interplay in order to identify and critique challenges. We highlight three interplay situations between multiple, diverse enactments of food sovereignty at multiple levels, and between food sovereignty and the broader institutional contexts within which they are embedded.