Globalization of the world’s economy, containerization, intermodalism and specialization have reshaped transport systems and the industries that are considered crucial for the international distribution of goods such as the port industry. Simultaneously, economies of location, economies of scope, economies of scale, optimization of production factors, and clustering of industries have triggered port regionalization and inland integration of port services especially those provided by container terminals. In this integration dry ports have emerged as a vital intermodal platform for the effective and efficient distribution of containerized cargo. Dry ports have enabled port and hinterland expansion increasing the competitiveness of container terminals at seaports. In consequence, container terminals and dry ports are establishing formal and informal relationships to strengthen the competitiveness of their hinterlands and to improve their role in the physical distribution of goods. This study assesses the characteristics of relationships between container terminals and dry ports. Such assessment is conducted based on a set of relationship characteristics proposed in a relationship assessment model for customer/supplier, in which dry ports are given the role of suppliers of port services to container terminals. In addition, the research assesses the impact of the relationships between container terminals and dry ports on inter-port competition. The main findings of the research led to conclude relationships between container terminals and dry ports are characterized by medium mutuality, low particularity, low co-operation, low conflict, low intensity, low interpersonal inconsistency, high power/dependence and medium trust. Additionally, it was concluded that such relationship characteristics impact inter-port competition in two main ways. In one hand by driving container terminals to maximize the utilization of dry port’s capabilities such as container transport/delivery, container storage, customs clearance, information systems and intermodal connections to industrial clusters. On the other hand, by constructing channels of interaction through which dry port’s benefits for hinterlands such as increase of container terminal capacity, reduction of road congestion, increase of modal shift and hinterland expansion are used as leverage in competition for containerized cargo.