Determinants of Purchase Intention Toward Beverages with Eco-Friendly Packaging: An Extended TPB-S-O-R Approach in Vietnam

Growing environmental concerns have intensified interest in sustainable packaging; however, consumer adoption of beverages with environmentally friendly packaging remains relatively low in developing markets. This study investigates the determinants of consumers’ purchase intentions toward such beverages in Central Vietnam using the extended Theory of Planned Behaviour (TPB), integrated with the Stimulus–Organism–Response (S-O-R) framework. Data were collected from 475 consumers and analysed using structural equation modelling (SEM). The results indicate low consumer familiarity with eco-friendly packaging labels, such as the Forest Stewardship Council (FSC), Green Dot Logo, and Compostable Logos, and only moderate adoption of sustainable packaging materials, with particularly low willingness to purchase beverages in fully recycled packaging. SEM findings show that attitude, perceived behavioural control, and perceived consumer effectiveness are significant direct predictors of purchase intention. Subjective norms and perceived environmental packaging knowledge show positive but marginal direct effects, whereas packaging functions have no significant direct effect. Attitude and perceived behavioural control act as key mediators. The study highlights the need to strengthen consumer awareness, improve recognition of eco-labels, and enhance social and psychological support to promote the adoption of environmentally friendly beverage packaging.