<p>Open Banking is often described as a technological or regulatory innovation. However, its value ultimately depends on consumers’ willingness to share financial data, making it a marketing challenge for financial services. This study investigates the factors influencing the intention to adopt Open Banking (OBA) and its relationship with the intention to use digital financial services (DFS) in Vietnam, a frontier market where digital infrastructure is improving but trust and customer readiness remain inconsistent. Using UTAUT2 and the Technology Readiness Index (TRI), and modelling trust through perceived security and regulatory support, the study analyses survey data from 458 respondents with PLS-SEM. The results show that technology readiness and trust are significant predictors of the intention to adopt Open Banking, while other UTAUT2 constructs exhibit more moderate effects. Facilitating conditions are not significant. Importantly, although the baseline model indicates a positive association, this relationship is not robust across alternative model specifications, and no mediating effect is supported. These findings challenge the assumption that Open Banking serves as a gateway to greater intentions to use DFS. Instead, the study shows that the intention to use DFS appears to be more strongly associated with trust and customers’ technology readiness, offering an alternative perspective on value creation in emerging digital financial ecosystems. For practitioners, the findings highlight the importance of building trust, enhancing customer readiness, and clearly communicating value in order to support engagement with data-sharing services in emerging digital ecosystems. Given the young and digitally reachable sample, the findings should be interpreted as most applicable to digitally engaged consumers rather than the broader Vietnamese population.</p>