This study investigates the antecedents of sustainable competitive advantages on marketing performance of horticultural products in Karo Regency, Indonesia. The research aimed to analyze the impact of trust, norms, and networks on sustainable competitive advantage and marketing performance. A total of 148 horticultural farmers from nine sub-districts in Karo Regency were surveyed, and data were analyzed using PLS SEM with WarpPLS software. The results showed that trust, norms, and networks had a positive and significant influence on sustainable competitive advantage. Trust, network, and sustainable competitive advantage had a positive and significant influence on marketing performance. However, norms had an insignificant positive effect on marketing performance. The study also found that sustainable competitive advantage mediated the indirect effects of trust, norms, and networks on marketing performance. The findings suggest that social capital, including trust, norms, and networks, plays a crucial role in enhancing sustainable competitive advantage and marketing performance in horticultural product marketing in Karo Regency. The study highlights the importance of building and maintaining social capital to improve the competitiveness and marketing performance of horticultural products in the region.This study investigates the antecedents of sustainable competitive advantages on marketing performance of horticultural products in Karo Regency, Indonesia. The research aimed to analyze the impact of trust, norms, and networks on sustainable competitive advantage and marketing performance. A total of 148 horticultural farmers from nine sub-districts in Karo Regency were surveyed, and data were analyzed using PLS SEM with WarpPLS software. The results showed that trust, norms, and networks had a positive and significant influence on sustainable competitive advantage. Trust, network, and sustainable competitive advantage had a positive and significant influence on marketing performance. However, norms had an insignificant positive effect on marketing performance. The study also found that sustainable competitive advantage mediated the indirect effects of trust, norms, and networks on marketing performance. The findings suggest that social capital, including trust, norms, and networks, plays a crucial role in enhancing sustainable competitive advantage and marketing performance in horticultural product marketing in Karo Regency. The study highlights the importance of building and maintaining social capital to improve the competitiveness and marketing performance of horticultural products in the region.