Current food systems face immediate and complex challenges in feeding a growing global population. It is necessary to mitigate the environmental impact of food systems while ensuring food security across the globe. Drawing on the example of recent multi-sectoral approaches which focus on the interconnections between public health and the environment, this work offers a narrative review and broader conceptual framework advancing two propositions. The first is that school meals systems have the potential to help enable sustainable food transitions. The second is that favoring well-planned plant-based meals in schools may strengthen this potential. The review and resulting framework highlight the relevance of seeking transdisciplinary dialogue and considering diverse sectors of society, such as public health, the environment, social protection, economic development, and community welfare. We review possible health benefits as well as possible economic and environmental outcomes, especially if school meals are sourced mainly from local communities and eco-friendly agricultural practices. Cross-sectoral implications related to social protection and community welfare are also identified and discussed, as well as potential pathways for materializing sustainable food transitions in schools.