Construction projects are frequently associated with a high incidence of cost overruns. To address this issue, the present study adopts a descriptive and survey-based approach to identify and rank the factors that contribute to construction costs. The study's statistical population comprises ten expert specialists, and the Fuzzy Decision-Making Trial and Evaluation Laboratory (DEMATEL) with Analytical Network Process (ANP) (DANP) technique is utilized to evaluate the research factors. Additionally, the Fuzzy DANP and Delphi methods are employed to rank the essential dimensions and criteria of the research. The study's findings reveal that environmental factors are the primary cause of construction cost overruns, followed by managerial factors and legal and administrative factors, respectively. Dynamic conditions often result in unpredictable challenges for environmental factors, making them a critical driver of construction cost overruns. Therefore, environmental factors play a significant role in contributing to construction cost overruns.