AbstractThe complex and complicated dispute over Urmia Lake is systematically studied in this research using an innovative methodology that incorporates the graph model for conflict resolution (GMCR) and the system dynamics (SD) approach in order to take into account the dynamic nature of the dispute. This intensified environmental dispute among key stakeholders took place between the mid-1990s and early 2010s and evolved in two courses of time. Within the first time frame, governmental decision makers began development projects related to the lake without seriously taking into account the warnings of environmentalists and somehow, ignoring the steps needed to completely protect the environment, causing a sharp drop in the lake’s water level. Within the second time frame and under the pressure of social protests due to environmental degradation of the basin and the drop in the lake’s water level, key decision makers changed their preferences over time and thus the dispute’s direction was changed dramatically. The dispute in each time frame is studied using SD-based GMCR and the changes of decision makers’ preferences within two time frames are examined using the feedback loops technique. The novelty of this research effort lies in developing a dispute management methodology that systematically takes into account the dynamic nature of dispute, a significant feature of complex dispute systems. Finally, the analysis of this real-life dispute, using the methodology employed, provides valuable insights about a better understanding of this complicated dispute over some courses of time so that a real and sustainable resolution can be provided.