Purpose We investigated consumers’ environmental, social and local beliefs and their impact on attitudes, subjective norms and willingness to pay for sustainable coffee in the understudied context of Thailand.Design/methodology/approach The study is based on a survey of 253 Thai consumers, analysed through an extended model of the theory of planned behaviour (TPB).Findings The study validates the TPB model in the Thai demographic, finding a significant positive impact of environmental and local beliefs and subjective norms on willingness to pay for sustainable coffee. More importantly, it proposes an extended model of TPB, stressing the central role of “local beliefs” in sustainable consumption in a Global South context.Originality/valueThis study demonstrates the importance of “localness” in the practice of sustainable consumption in Thailand, namely the beliefs in the support for the local economy and prosperity for the local community. This expands our understanding of the heterogeneous meanings associated with the practice of sustainable consumption in a South-East Asian context.