Sustainability has garnered increasing interest among stakeholders, driving higher investments in ESG (Environmental, Social, and Governance). In the event sector, sustainability is often overlooked in favor of purely financial considerations, leading to adverse environmental and social impacts. To address this challenge, ISO 20121 has emerged as a strategic tool to guide the organization of sustainable events in alignment with ESG principles. Despite the relevance of this topic, no studies were found in the literature that link ISO 20121 with ESG. Therefore, this study evaluates the contribution of ISO 20121 to ESG. Three experts analyzed the standard using a relationship matrix based on MSCI's (Morgan Stanley Capital International) ESG criteria to achieve this. A quantitative modeling approach was applied, employing the Intuitionistic Fuzzy TOPSIS method. The results indicate that ISO 20121 contributes to ESG, with the most significant impact observed in the governance pillar. Subclause 6.1, which addresses actions for risks and opportunities, was most aligned with ESG principles. It is concluded that developing a management system based on this standard can enhance organizations’ ESG performance and add value to their image.