In a decision-making process, a systematic method to manage and measure negotiation aspects provides crucial information to negotiators and has emerged as a key factor to determine agreements’ success or failure. Accordingly, this work aims at presenting a negotiation support system which provides functionalities to create negotiation models through settlements’ historical information. These models are interpreted as Fuzzy Cognitive Maps (FCM) and the software tests as the convergence of each model. Thus, the system intends to facilitate decision-markers to predict future negotiations behavior and, consequently, improve the chances of an agreement. Besides, this work examines a case study through the lenses of FCM to illustrate real negotiations outcomes and expected value quantifications. The proposal is to compare a model map developed from old negotiations with the results obtained through FCM simulations. As a result, from the use of these mechanisms, negotiators could better ...