Several countries have implemented warnings on unhealthy foods and beverages, with similar policies under consideration in the U.S. and around the world. Research demonstrating food warnings' effectiveness is emerging, but limited scholarship has evaluated the ethics of food warning policies. Using a public health ethics framework for evaluating obesity prevention policies, we assessed the ethical strengths and weaknesses of food warnings along multiple dimensions: 1) Health behaviors and physical health, 2) Psychosocial well-being, 3) Social and cultural values, 4) Informed choice, 5) Equality, 6) Attributions of responsibility, 7) Liberty, and 8) Privacy. Our analysis identifies both ethical strengths and weaknesses of food warnings, including that: 1) warnings are likely to generate important benefits including increased consumer understanding and informed choice, healthier purchases, and potential reductions in obesity prevalence; 2) warnings evoke negative emotional reactions, but these reactions are an important mechanism through which food warnings encourage healthier behaviors and promote informed choice; 3) warnings appear unlikely to have ethically unacceptable effects on social and cultural values, attributions of responsibility, liberty, or privacy. Current research suggests we continue to pursue food warnings as a policy option for improving public health while simultaneously conducting additional research on the ethics of these policies. Future research is especially needed to clarify warnings' effects on stigma and to characterize the balance and distribution of costs of and benefits from implementing warning policies.