The high cost incurred by the resolution of conflicts is largely affected by the existing adversarial nature of the construction industry along with the use of non-efficient dispute resolution methods in construction projects. This paper studies opinion dynamics in the negotiation of construction disputes while trying to understand the behavior and extremism of each contractual party. The developed model uses an agent-based approach to show how each agent’s attitude can influence the negotiation process when solving a dispute. It can also be used to highlight the importance of alternative dispute resolution (ADR) methods and the use of a mediator in helping parties initiate negotiation and decrease the number of negotiation cycles needed to converge. The results showed that negotiation is not only affected by the attitude and character of the agents involved but it is also influenced by the delivery method of the project and the level of intensity of each agent. It was found that when the project is delivered through an Integrated Project Delivery (IPD) method, parties are more flexible and cooperative and will reach agreement within few negotiation cycles.