This study investigated how contextual factors influenced the sustainability of outcomes from a 3-year, state-funded professional development program that provided science assistance for K-2 teachers in small, rural school districts. The research used a case-study approach with a purposive sample of five elementary schools that varied in instructional time in science several years after the funding period. The primary data sources were teacher surveys and interviews conducted 2 and 3 years after the end of the professional development program. The findings highlight variations across schools and the influence of principal support, resources, collegial support, personal commitment, and external factors. The research holds practical implications for enhancing long-term sustainability of professional development outcomes in science education.