One of the major concerns raised by people using negotiation processes is about the fairness or justice of the process. Individuals undertake negotiation to derive better outcomes than would otherwise occur, which requires them to engage in interest-based negotiation. But interest-based negotiation focuses upon the interests of the disputants rather than any objective legal measures of "fairness" – that is, legal justness, not the more commonly accepted negotiation concept of meeting the interests of all parties equally. It is vital to investigate how to develop measures, or at the very least principles, for the construction of legally just negotiation support systems. This article discusses processes that, when applied, will encourage fairness and justice in the development of negotiation support systems. Such processes include providing enhanced transparency, supporting bargaining in the shadow of the law, and allowing for limited discovery.