The international harmonization of technology-related regulations seeks certain norms across diverse contexts. Harmonization efforts are based primarily on the promulgation of state-centered command and control forms of regulation, though they may also be accompanied by the diffusion of more plural approaches that are decentered from the state. We contrast the ways in which the “proper” use of transgenic cotton seed technologies is understood in harmonizing regulations with the way this technology is used in practice in regions of Argentina and China. We find divergence that poses challenges for both state-centered and decentered approaches to harmonization. While state-centered approaches are blind to some critical processes on the ground, decentered strategies are found wanting in situations where norms remain deeply contested amongst actors situated in very uneven power relations. In both cases, we find that establishing and securing norms that are socially just and environmentally sustainable means attending much more explicitly to the political economies in which technological practices actually take root.