At least eight U.S. states currently offer universal free school meal programs, providing meals at no cost to all students regardless of household income. While marketing campaigns may help increase student participation, limited research has examined what message content and design most effectively motivate parents to encourage school meal use. This qualitative study explored parents’ perceptions of messages promoting school meal participation. Semistructured online interviews were conducted in February and March 2024 with parents of children in grades 1–5 who did not frequently eat school meals and lived in states with universal free meal programs (N = 18; 14 women; 6 Spanish-speaking). Interviews examined reactions to message topics (eg, convenience, nutrition) and design elements (eg, cartoons, photographs). Transcripts were analyzed thematically using in vivo coding. Parents viewed messages emphasizing convenience and cost savings as most motivating. Many also believed school meals support children’s social and developmental growth. Messages about nutritional quality were motivating only when parents already trusted the healthfulness of school meals. Notably, some parents were unaware that meals were free despite living in eligible states. Regarding design, parents preferred concise messages with bold colors, modern layouts, and credible references or statistics. Overall, campaigns may be more effective if they emphasize convenience, financial savings, social benefits, and clearly communicate that school meals are free for all students. Future research should test whether such campaigns increase participation.