Abstarct: The global fashion industry, due to its extensive environmental and social consequences, faces increasing pressure to move towards sustainability. The COVID-19 pandemic exacerbated this necessity by exposing the vulnerabilities of global supply chains. This research aims to identify and structurally analyze the drivers of sustainability in the fashion supply chain under crisis conditions, seeking to open the "black box" of complex and hierarchical relationships among these factors to provide a roadmap for managers and policymakers to design more resilient strategies. The statistical population of this study comprised academic experts and senior managers in Iran's fashion and apparel industry. Data were collected through the expert judgments of this panel using structured questionnaires. The significance of this study lies in providing an integrated model for understanding the dynamics governing sustainability in crisis situations, a topic overlooked in previous studies that mostly focused on listing factors. Analyzing this is essential for enhancing the industry's resilience against future disruptions. This research employed a three-stage hybrid methodology. First, using the Fuzzy Delphi method, 39 key drivers were screened and finalized from an initial list extracted from the literature. Subsequently, using Interpretive Structural Modeling (ISM), a six-level hierarchical model of causal relationships among these drivers was developed. The results indicated that drivers such as "top management commitment" and "explicit policymaking" are at the most fundamental level (Level VI), acting as prerequisites for other factors. Finally, MICMAC analysis confirmed that the system is highly interconnected and that the identified foundational drivers have the most significant driving power throughout the system. The main conclusion is that achieving sustainability is a top-down process originating from strategic and governance commitments. This model is applicable in the industry as a diagnostic and strategic tool, helping managers to effectively allocate resources and maximize the impact of their sustainability strategies by focusing on key levers.