Social commerce(s-commerce), which emphasizes the predominance of customers, has become an important tool of company social marketing and provides new challenges to businesses in attracting customers. Based on customer-dominant logic theory, this study presents a model of the impact of electronic customer-to-customer interaction(eCCI) on customer stickiness with the mediation effect of customer value co-creation dimensions, specifically functional value and hedonic value in the s-commerce context and self-efficacy as a moderator in light of customer-dominant logic. This study adopted a survey method and obtained data from users in two s-commerce sites in China. The statistical technique of partial least squares structural equation modeling (PLS-SEM) and the analytical process of necessary condition analysis (NCA) were employed to analyze the data. The PLS-SEM results indicate that eCCI influences customer value co-creation, which in turn affects the consumer stickiness of s-commerce sites.The moderated mediation results showed that self-efficacy moderated the relationship between eCCI and customer stickiness.The NCA results identified the eCCI is meaningful and significant necessary conditions for fostering customer value co-creation and customer stickiness. The combined findings demonstrated to researchers and practitioners how to identify the critical factor that influence customer value co-creation and customer stickiness. The study provides novel insights into the mechanism underlying why consumers “stick” to s-commerce websites. Furthermore, the moderated mediation model extended customer-dominant logic and demonstrated the moderating influence of self-efficacy. The theoretical and practical implications of these findings are discussed.