Government investment in ports, as one of the main pillars of maritime transport infrastructure development, plays a vital role in strengthening economic growth and enhancing the country’s position in the blue economy. The aim of this study is to identify and prioritize the factors influencing government investment in Iranian ports within the framework of the blue economy. To this end, the Fuzzy Delphi method was employed, and data were collected and analyzed based on the opinions of experts in the fields of economics and maritime transport. The results revealed ten key factors influencing government investment in ports, among which “government revenue status” and “its financial capacity with an emphasis on dependence on oil and tax resources” play the most critical roles. Other influential factors include the volume of maritime trade and global demand, the quality and extent of domestic transport infrastructure, government economic policies, the geographical location of ports, the intensity of regional competition, the level of technology and automation, security and safety requirements, the level of foreign investment attraction, and attention to environmental sustainability. The findings indicate that government investment in ports, in addition to macroeconomic variables, is also affected by institutional, regional, and environmental factors. Accordingly, strengthening the government’s financial sustainability, developing transport networks, leveraging geopolitical advantages, and enhancing technological capabilities can pave the way for the sustainable development of Iranian ports and their more effective contribution to the realization of blue economy objectives.