Research background:E-commerce is a key driver of global economic growth, influenced by technological, economic, and social factors. While prior research has focused on economic andtechnological determinants, the macroeconomic role of social capital—defined by trust, norms, and networks—remains underexplored. Social capital reduces transaction uncertainty, strengthens consumer trust, and facilitates business expansion, yet its cross-national impact on e-commerce adoption requires further investigation. Purpose of the article: This study examines how social capital influences e-commerce development in European countries, exploring whether higher levels of social capital contribute to greater e-commerce adoption and transaction intensity while accounting for economic factors such as GDP per capita and disposable income. Methods: The study analyses panel data from 28 European countries (2015–2023) using the Social Capital Index (SCI) to measure national trust and networks. E-commerce activity is assessed based on online purchase participation and business turnover from digital sales. Panel data models with fixed and random effects are applied to examine the relationship between social capital and e-commerce adoption. Findings & value added: The results confirm that social capital significantly influences e-commerce adoption. Countries with stronger trust networks and social cohesion see higher participation in digital commerce. Economic conditions, including GDP per capita and disposable income, moderate this effect, with wealthier nations benefiting more from trustdriven e-commerce expansion. The study underscores the importance of fostering social capital to enhance consumer confidence, lower transaction costs, and promote sustainable digital market growth, offering policy recommendations to strengthen trust mechanisms and support e-commerce ecosystems.