Purpose: Following the emergence of Web 2.0 technologies, social commerce has been viewed as an inseparable part of today's business environment. Social commerce is a recent version of e-commerce, which has rapidly become a new interesting field for both practitioners and academics. To improve social commerce success, managers should be aware of what encompasses social commerce quality, how consumers sense it and how it is assessed. Though, despite the importance of social commerce, designing of scales for measuring the social commerce quality has rarely been explored. Therefore, the purpose of this study is to develop a new scale for measuring the social commerce service quality comprehensively. Design/methodology/approach: To obtain the research objective, in the first step, a comprehensive literature review along with focus group discussions was conducted to theoretically conceptualize service quality dimensions and measures. Then, for evaluating the proposed scale via social commerce customers, the survey method was used. Finally, the verified measures were weighted and ranked using fuzzy analytic hierarchy process. Findings: The findings showed that social commerce service quality is a hierarchical and multidimensional construct consisting of six key dimensions including information quality, social interaction quality, design quality, functional quality, social trust/security and social support. Research limitations/implications: The study results assist managers to improve the quality of social commerce services through increasing the awareness of customers' perceptions and expectations concerning social service quality. They further help managers to understand systematically all dimensions of social commerce service quality, which may lead to reduce the risk of social commerce adaptation failure and consequently increase the customers' satisfaction. Originality/value: The role of service quality in acceptance and success of social commerce has been emphasized by many academics and practitioners. However, review of the previous literature shows that inadequate studies in this field have been conducted so far. The main contribution of this study is conceptualization and development of a validated scale for measuring the social commerce service quality. This scale provides a useful instrument for researchers who wish to measure the service quality of social commerce and for managers who want to improve the perceived quality of their services. [ABSTRACT FROM AUTHOR]