25 pages, Decreasing the consumption of meat and dairy has been identified as an effective strategy for protecting the health of humans and the planet. More specifically, transitioning to diets that are lower in animal-source foods and higher in fruits, vegetables, legumes, and whole grains offers a promising opportunity to better align consumer behaviors with contemporary nutritional and ecological goals. However, given the limited understanding of how these changes in dietary behaviors can be best promoted, there is a need to explore the merits of community-based approaches to meat reduction and their capacity to advance more sustainable practices of eating at the individual, household, and community levels. To address this gap in the literature, we surveyed more than 100 American households participating in a communitywide, 12-week-long Meatless Monday challenge and tracked the changes in their knowledge, attitudes, beliefs, and food choices over a nine-month period. The case study provided herein highlights a number of key findings from our evaluation. Most notably, our results demonstrate the value of community-based efforts in initiating and maintaining dietary behavior change and provide preliminary insights into the unique roles of multilevel interventions and diverse stakeholder engagement in promoting healthier, more sustainable diets.