Sustainability starts with the consumer: How green consumption shapes business model transformation a COM-B analysis of green purchase behavior in Vietnam’s agriculture

This study is motivated by the need to align national sustainability goals with real consumer behavior by identifying the barriers that block green purchase follow-through. We conducted a quantitative, cross-sectional, online survey of 684 Vietnamese consumers using multi-item scales for COM-B constructs, Perceived Consumer Effectiveness (PCE), intention, behavior, and greenwashing. Partial Least Squares Structural Equation Modeling tested measurement quality, structural paths, mediation, moderation, and predictive relevance. The model explained 58.9% of intention and 52.5% of behavior. Capability and Opportunity significantly increased intention, whereas motivation did not. PCE increased intention and behavior, and intention predicted behavior. Perceived greenwashing weakens the intention-behavior link. Mediation analyses showed that Capability, Opportunity, and PCE influenced behavior via intention, with PCE also exerting a direct effect. PLSpredict indicated a good predictive relevance. These results indicate that improving consumer capability, access/affordability, and efficacy beliefs can raise green purchasing, but claim credibility is critical to convert intention into action, offering actionable levers for aligning consumer demand with sustainable agri-food business models promoting more sustainable agri-food practices in Vietnam.