Abstract To tackle environmental issues and ensure compliance with regulations, three ports in Vietnam and two ports in Cambodia implemented an Environmental Management System (EMS). The first steps of the EMS were completed during the period 2006–2007, with the establishment of the Port Environmental Policy, the Register of Environmental Aspects and an EMS Programme. Priorities in environmental protection have been identified for each of the ports. The initial assessment of the EMS, based on the documented EMS, was completed by experts from the ECOPORT Foundation, who issued a Port Environmental Review System (PERS) certificate for the ports. This paper presents an assessment of the implementation of the EMS through the eyes of various groups of port stakeholders. The second focus is on the manner of involving stakeholders in the EMS process, which has stakeholder participation as one of its core principles. The assessment was done via interviews with the environmental coordinators or managers at each port, as well as key port stakeholders. Eight groups of stakeholders are identified and classified into internal/external and voluntary/involuntary categories. Their salience is then assessed based on their legitimacy, power, urgency and proximity. The findings show that while ports are perceived as sources of environmental problems, they are also seen as important economic powerhouses. EMS is therefore needed at the ports to ensure their environmental performance is in line with their economic contribution. However, ports generally view other stakeholders as outsiders and exclude them from the process of designing environmental protection measures. Even though the stakeholders are strongly interested in contributing more to the process, there is no concrete plan for involving them in the management of the port.