Water scarcity and unsustainable water management have become major challenges threatening agricultural development in arid and semi-arid regions. Existing water sustainability indicators often fail to comprehensively address the environmental, economic, social, institutional, and managerial dimensions of agricultural water management. Therefore, this study aimed to identify the drivers of agricultural water unsustainability and develop a participatory Agricultural Water Sustainability Index (AWSI). A mixed-methods approach was employed in Hamadan Province, Iran. Data were collected through semi-structured interviews, open-ended questionnaires, and expert surveys. The Decision-Making Trial and Evaluation Laboratory (DEMATEL) method was used to analyze causal relationships among factors affecting agricultural water sustainability.

. In addition, Integer Linear Programming was applied to select the most representative indicators. Results revealed that managerial, economic, structural, legal, and strategic barriers were the most influential drivers of agricultural water unsustainability. The final sustainability index consisted of seven dimensions and twenty-four indicators, including water resources, balance between water supply and demand, agricultural water productivity, agricultural water consumption, environmental quality, social-human capital, and institutional support. Findings indicate that sustainable agricultural water management requires an integrated approach that simultaneously addresses physical, environmental, economic, social, and institutional dimensions. The proposed index provides a practical framework for monitoring agricultural water sustainability and supporting evidence-based water policy making.