Along with the significant growth of the sharing economy in recent years, its effect on the economy, society, and the environment at the level of governments, academic communities, and researchers has been widely discussed. One of the main debates is identifying the side or negative effects of the sharing economy as well as its positive effects. Studying the cause-effect relationship of the variables affecting sustainability in the sharing economy context can provide valuable results for firms. For this purpose, fuzzy cognitive maps have been used. Based on the literature review, the sharing economy’s essential variables that affect sustainability were identified, and using the Fuzzy Delphi method, these variables were localized. Snapp and Tap30 were selected as two of the largest platforms in the Iranian transportation sector. Fuzzy cognitive maps based on aggregated opinions of experts were inputted to the Mental Modeler online software to drawn the cognitive map of this research. The degree of centrality index, i.e., the summation of input and output degree, was used to identify the most relevant sustainability variables. Consequently, the incentives to make a greater use of the platform, the income of drivers, the monopoly power of platforms, the price of services, the higher service quality of platforms, the use of private vehicles by passengers, and the change of traffic in cities were identified as variables with the greatest effect on stability. Four positive loops and one negative loop were identified among these seven variables in the cause-effect analysis. In the final section, some suggestions are presented based on each loop.
