Sustainable development is viewed as a global goal to solve social, and encouraging stakeholders to become concerned about ecological conservation and to make efforts in engaging in sustainable activities is vital. Though the motivation behind consumer willingness to support the activities of social enterprises should be examined, the literature offers only limited work from the consumer perspective. This study thus integrates relationship marketing theory and an ethical decision‐making model to explore consumers' ethical judgments and behavioral intentions toward sustainability activities. The results show that the impact of perceived value influenced by social and economic benefits on consumers' ethical judgment and behavioral intentions toward sustainability activities is more powerful than that of altruism and environmental value. When consumers' judgments are positive and ethical, their ethical consumption involving sustainability activities and loyalty intentions toward social enterprise will improve. These findings identify research gaps for future research and offer important implications for businesses.