This study examines the sustainable competitive advantage and marketing performance of horticultural products in Karo Regency, influenced by trust, norms, and networks. The research involved 148 horticultural farmers across nine sub-districts in Karo Regency. Data were analyzed using PLS SEM with WarpPLS software. The results indicate that trust, norms, and networks have a positive and significant direct influence on sustainable competitive advantage. Additionally, trust, network, and sustainable competitive advantage have a positive and significant direct influence on marketing performance. However, norms have a positive but insignificant effect on marketing performance. The study concludes that social capital, particularly trust, norms, and networks, plays a crucial role in enhancing sustainable competitive advantage and marketing performance in the horticultural sector of Karo Regency.This study examines the sustainable competitive advantage and marketing performance of horticultural products in Karo Regency, influenced by trust, norms, and networks. The research involved 148 horticultural farmers across nine sub-districts in Karo Regency. Data were analyzed using PLS SEM with WarpPLS software. The results indicate that trust, norms, and networks have a positive and significant direct influence on sustainable competitive advantage. Additionally, trust, network, and sustainable competitive advantage have a positive and significant direct influence on marketing performance. However, norms have a positive but insignificant effect on marketing performance. The study concludes that social capital, particularly trust, norms, and networks, plays a crucial role in enhancing sustainable competitive advantage and marketing performance in the horticultural sector of Karo Regency.