This article introduces a simulation ontology to support terminal planers, operator and managers in the design and management of seaport container terminals. Due to the increasing requirements of shipping companies regarding efficiency, quality and price for the handling processes at container terminals, the use of integrated approaches for improving the performance has grown significantly. Simulation, which has proven highly beneficial in production and logistics, represents an adequate tool to deal with complex systems like container terminals. However, building simulation models requires much time and simulation software know-how. To counteract this effect, this article presents a simulation ontology of seaport container terminals, which supports the user in building specific simulation models. Since the simulation model is automatically created through the ontology framework, neither the personnel skills nor the time available to build the simulation model represent significant hurdles. Furthermore, the proposed ontology can dramatically reduce the time required to test a specific configuration of a container terminal and/or a particular management policy. The ontology framework consists of a user interface with database, where the user can specify elements and their parameters, an atom library representing all elements of the system and software application, which is used to automatically build the simulation model.