This study aims to identify and analyze the sustainable supply chain management (SSCM) implementation barriers in the context of Iran to determine the barriers and establish a cause-and-effect relationship between them. The Fuzzy Delphi Method (FDM) is used to assess the barriers to SSCM implementation in Iran, and a fuzzy decision-making trial and evaluation laboratory (DEMATEL) is used to obtain qualitative assessments from multiple experts regarding how to mitigate the impact of the barriers. To validate the proposed methodology, out of 20 barriers identified through the literature review and 9 more barriers suggested by experts, 26 barriers are identified to be relevant to the context of Iran using FDM. Six SSCM implementation barriers (i.e., economic sanctions; banking problems; economic instability; high inflation rate; lack of regulation and guidance from the government and lack of a globally competitive environment) were determined as important barriers in the cause group. All of them are related to Iran’s economic situation, the economic sanctions against Iran, and the government’s neglect of the importance of sustainability issues, all of which are obviously out of the companies’ control; moreover, the impact-relation map for each has been developed to facilitate the visualization of its interactions (i.e., influencing and influenced) with other barriers. The outcomes achieved are unique to Iranian companies and cannot be generalized to every company in other countries; however, the proposed approach might serve as a foundation for analyzing and comprehending the interactions between barriers. The suggested technique would identify the most effective areas for directing resources and efforts to reduce the effects of barriers to successful SSCM implementation.