ABSTRACT Disputes have an extremely high negative emotional workload. Based on the approach of the Emotion as Social Information Model (EASI), we intend to demonstrate how expressing negative emotions plays a different role in solving a dispute than feeling negative emotions. The participants were 43 professional negotiators managing a dispute escalated by a confederate in three conflict levels during a chat interaction between a supervisor and a subordinate. The trained judges evaluated the negative emotions expressed, problem-solving behaviours and the effectiveness in solving disputes. As the main outcome, we demonstrate that expressing negative emotions increases problem-solving behaviour and effectiveness in solving a dispute, whereas feeling negative emotions (anger) decreases them. Additionally, our findings show that one mechanism which explains the effectiveness in solving disputes is the positive influence of expressing negative emotions on problem-solving behaviour. Practical and theoretical implications are discussed.