Background: Treatment implementation is not just one thing but rather is a multifaceted process that includes treatment delivery, treatment receipt, and treatment adherence. As such, local variations in implementation and service delivery of interventions are an inevitable. Purpose: To assess implementation fidelity of a multi-site experiential nutrition education program. Setting: Multiple sites throughout the continental United States. Intervention: An experiential nutrition education program. Research Design: A concurrent mixed methods design was used to assess implementation fidelity. Data Collection and Analysis: Multiple methods of data collection and analysis were used including observations, interviews, survey questionnaires, and extant data. Findings: Although implementation fidelity varied over program sites, overall implementation fidelity was very good and when it varied, it varied to local site needs and context. (Contains 4 tables.)