Alive & Thrive (A&T) applied principles of social franchising within the government health system in Viet Nam to improve the quality of interpersonal counseling (IPC) for complementary feeding (CF). These efforts were combined with a national mass media (MM) campaign and community mobilization (CM). The study evaluated the impact of this enhanced, intensive IPC + MM + CM intervention compared with standard IPC and less intensive MM + CM on complementary feeding practices and anthropometric indicators. The results showed that the intensive mode (at-scale social franchising approach to improve IPC) delivered through the existing health care system, significantly improved CF practices, but not child growth, among mothers who used counseling services at least once. There are several lessons learned from this novel social franchise approach to deliver high-quality IPC at scale and to improve CF practices. The franchise start-up involved implementation steps to advance the model in 15 provinces simultaneously, ensuring that lessons learned could be broadly applied to other geographic areas. Extensive formative research was used to develop the behavior change interventions, including the IPC service package, the franchise brand, educational materials, and MM. The roll-out and scale-up of the franchise operations were carried out in conjunction with routine monitoring of quality and coverage, supervisory, and management approaches that supported implementation. However, a even greater impact may be achieved with strategies designed to increase service utilization.