With the rapid development of technology, many technology-based self-services (TBSS) are gradually replacing traditional personnel services, and service quality is equally important for this emerging service mode.  Previous research examined the influences of technology characteristics and customer traits on the TBSS quality, while social factors in the physical environment are neglected.  Based on servicescape theory and social impact theory, this research focuses on indirect customer- to-customer interaction ( other customers are merely part of the scene) , which is a critical social factor in TBSS context.  Three studies are implemented to explore the effect of the indirect customer-to-customer interaction on perceived TBSS quality.  The results show that the indirect customer-to-customer interaction has a negative impact on service quality, and negative e- motion mediates the link between them (study 1) ; service valence (study 2) and self-efficacy (study 3) moderate the mediation effect of negative emotion.  Specifically, compared with service failure, the mediating effect of negative emotion is greater in successful service; compared with high self-efficacy customers, the mediation effect of negative emotion is greater for low self-efficacy customers.  This paper extends the scope of research on the influencing factors of TBSS quality and uncovers the underlying mechanism and boundary conditions of the impact of indirect customer - to - customer interaction on TBSS quality.  The findings will enable the service providers to understand the impact of other customers' presences on TBSS in the physical environment and provide guidance and reference for servicescape management and the design of reasonable service physical environment.