Objective: This article describes Mayors Mentoring Mayors (3M), an initiative of the Arkansas Coalition for Obesity Prevention (ArCOP), which expanded to five states to become the signature community initiative of the Mid-South Transdisciplinary Collaborative Center (Mid-South TCC) for Health Disparities Research. Methods: The 3M program is an extension of the Growing Healthy Communities (GHC) program, which sought to build capacity within communities to reduce obesity by implementing policy, system and environmental (PSE) changes that support healthy living. GHC where the mayor was involved had the most significant changes toward better health. These mayors were recruited to share their successes, lessons learned, and best practices with their colleagues through a series of Lunch & Learns. Following the GHC and 3M models, a multi-state approach to expand 3M to five additional states was developed. ArCOP partnered with the Mid-South TCC to recruit mayors in the five states. Results: Five Lunch & Learn events were held across Arkansas between March and May 2015, with a total of 98 participants (40 mayors, 37 community leaders, 21 guests). Each regional Lunch & Learn had 1-2 host mayor(s) in attendance, with a total of 9 host mayors. For the 3M regional expansion project, eight GHC Recognition Applications from five states were submitted. Five communities, designated as Emerging, were funded to implement GHC projects. Conclusion: ArCOP successfully engaged mayors, elected officials, and stakeholders who can influence policy across Arkansas as well as in an additional five states in the Mid-South TCC region to implement obesity PSE prevention strategies.