This paper proposes a decision support system for optimizing operations on the quayside of a container terminal. Due to the existence of multiple parties involved in the decision making processes within port operations, it is essential to pay attention to each parties' concerns and demands which by nature are frequently conflicting with each other. This calls for a DSS that offers the flexibility of adjusting the balance within conflicting objectives, guiding the decision maker towards the final decision. Consequently, this study provides a DSS that determines the berthing and crane allocations simultaneously. To show the practical application of the DSS presented, a real life case study at a container terminal has been conducted. Implementation of the model shows that improvements ranging from 10% to 25% on service time and costs can be attained.