“Why Do We Buy Green Products?” An Extended Theory of the Planned Behavior Model for Green Product Purchase Behavior

Many consumers are concerned about environmental issues and have expressed interest in purchasing green products. However, actual sales of green products are still not as high as expected. Therefore, marketers of green products may need to investigate the factors driving green purchase behaviors. In this study, we proposed an extended theory of planned behavior (TPB) model that links consumers’ environmental concerns, perceived image of the company, consumer innovativeness, and environmental knowledge with green product purchase behavior. We applied a quantitative approach to collect the data via online questionnaires through Amazon MTurk. With 974 useable samples, the data were analyzed with structural equation modeling (SEM) using Smart PLS. The results showed that green purchase intention positively and significantly affects green purchase behavior. Moreover, the multigroup analysis revealed that the direct influence of green purchase intention on green purchase behavior is higher in developing countries than in developed countries. Regarding the direct effect on green purchase intention, attitude toward green products, perceived consumer effectiveness (PCE), environmental concern, and company’s perceived green image are significant antecedents of the intention to purchase, with attitude toward green products being the most robust antecedent among the three. However, subjective norms do not act as a direct antecedent of purchase intention. For the indirect effect on green purchase intention, four main antecedents (attitude toward green products, subjective norms, PCE, and environmental concerns) indirectly impact purchase intention via the mediating role of the perceived green image of the company. This study contributes to existing literatures via extending the TPB model. Regarding attitude-intention-behavior model, we found that environmental concern complements the model as an antecedent of green purchase intention. Moreover, a company’s perceived green image mediates the relationship between four antecedents and green purchase intention. Therefore, marketers of green products may also enhance future purchases by promoting the green image of the company. Particularly, we found that environmental knowledge positively moderates the relationship between environmental concern and a company’s perceived green image. We added on the empirical evidence that PCE plays a crucial role in stimulating green purchases as its direct positive influence on green purchase behavior is larger than that of green purchase intention. Moreover, consumer innovativeness positively moderates the relationship between PCE and green purchase intention.