To address obesity and diet-related chronic diseases in the United States, organizations such as the Robert Wood Johnson Foundation and the Institute of Medicine have encouraged the use of voluntary engagement strategies among stakeholders. By using public-private partnerships as well as networks, alliances, and coalitions, voluntary engagement can translate evidence-informed dietary recommendations into effective policies and actions and into innovative products and services. We offer six guiding principles and a decision-making framework that stakeholders can use to ensure that partnerships are accountable and effective in their pursuit of health-related goals. We apply the principles and framework to four national partnerships of US food, beverage, and food retail industry stakeholders working to prevent child obesity and to promote healthy food environments through product reformulation and healthy food retail incentives. We conclude that partnerships should be evaluated for their synergy, accountability, and effectiveness at achieving the partners’ objectives. Independent evaluations will help build credibility and public trust in the capacity of voluntary engagement strategies to promote healthy food environments and positively influence public health.