The Healthy Living Ambassador Program brings health, teen leadership, and teamwork to California's elementary school gardens through interdisciplinary UC Cooperative Extension collaboration, community-based partnerships and teen teaching. During spring 2015, teen ambassadors trained by Extension educators and volunteers at UC Elkus Ranch in San Mateo County taught nutrition science, food cultivation and healthy living skills in an 8-week, garden-based, after-school nutrition and physical education program for elementary school children in an urban setting. We conducted a pilot study using a mixed-methods approach to measure and explore the program's impact on children's vegetable selection and consumption preferences, as well as perceived self-efficacy in teen healthy living behavior. The children trended toward an increased preference for gardening, cooking and science, and teens displayed an increase in perceived health self-efficacy.