Social commerce is a new phenomenon that is less considered indifferent researches. In this type of commerce, consumers have become able to generate content about different products/services and share their information and experiences with other people. This is very important for producers and providers and may include opportunities and threats. Due to these circumstances, investigating on consumer behavior is vital. Hence, this study aims to provide a framework for the factors affecting social customer participation in social commerce using Stimuli-Organism-Response model. The present research is an applied research in terms of objective and descriptive-survey (correlational type) in terms of data collection. Statistical population of the research consists of three popular social networks in Iran (i.e. Facebook, Cloob, and Telegram). Furthermore, the research sample size was estimated to 360 users using quota and snowball sampling method. The obtained results were analyzed using PLS-SEM approach. The results showed that in investigating the effect of stimuli variables on organism of website quality or practical program, perceived interactivity and subjective norms have a positive and significant effect on quality relationship, social support and attitudes toward social commerce, respectively. Also social commerce constructs affect social support and attitudes toward social commerce. In addition, perceived interactivity has a positive and significant effect on attitudes toward social commerce. Secondly, social support, relationship quality and social attitude together with subjective norms are positively associated with social commerce as the response. Finally, social support has a significant positive impact on quality relationship which in turn influences attitudes toward social commerce.