Soda taxes are controversial. While proponents point to their potential health benefits and the public projects that could be funded with their revenue, critics argue that they are paternalistic and regressive. In this paper, we explore the prospects for designing a just soda tax, one that appropriately balances the often-competing ethical considerations of promoting social welfare, respecting people’s autonomy and ensuring distributive fairness. We argue that policymakers have several paths forward for designing a just soda tax, but that the considerations relevant to ethical policy design are more complicated than is sometimes acknowledged.