The competency characteristics of managers affect decisions that identifying the strategies in an organization. Similarly, the strategies for sustainability issues are also related to the managers’ competency on sustainability. Thus, for better sustainability performance, the managers are expected to possess competencies in this direction. In this context, this study is aimed to evaluate the operations managers’ competencies in terms of environmental sustainability in ports, which have huge effects on the physical and biological environment. For this purpose, one of the Multi-Criteria Decision Making (MCDM) methods, Analytic Network Process (ANP) was used to evaluate the priority weights of 15 competencies. Within a framework of container ports/terminals, the findings of this study show that “management skill”, “emergency procedures”, and “safety management” are the most primary competencies of port operations manager (POM) in terms of port environmental sustainability performance (PESP). The model used in this study can contribute to human resourcing and personnel training processes of ports.