Background: The Healthy, Hunger-Free Kids Act of 2010 authorizes the U.S. Department of Agriculture (USDA) to establish nutritional standards for all foods sold in schools participating in federally funded meal programs. These foods, known as competitive foods, are commonly found in school cafeterias, vending machines, fundraisers, and snack bars and are associated with unhealthy dietary patterns. However, little is known about the regulatory process and opportunities for public participation to improve school food. Aims: This study investigates public commentary on the USDA's proposed rules governing competitive foods in schools. Methods. On February 8, 2013, the USDA's Food and Nutrition Service solicited public comments via Regulations.gov. A corpus of 247,871 public comments was obtained. Duplicate and near-duplicate comments were removed resulting in 3,032 unique comments. Two researchers content analyzed 10% of the sample, removing nonrelevant comments (n = 249). Results: A majority of commenters are women, and mention their affiliation. Comments tend to be short, and exhibit low levels of complexity. An overwhelming majority of comments expressed concerns about the public health of youth vis-à-vis the new rule, whereas a small but vocal minority opposed the rule for financial and labor reasons and/or opposition to further government regulation. Discussion: Commentary on proposed rules should be specific, avoiding off-topic remarks. Commenters should be strategic, include their credentials, and provide a rationale for their position. Conclusion: The rules governing competitive foods are poised to reverse the childhood obesity epidemic, and public commentary may shape these rules.