Innovative approaches such as the use of technology in negotiations raise questions of how technology interacts with the manifold contextual factors that play a role in negotiations. In this article, we introduce a theoretical framework that seeks to inform the design of Negotiation Support Systems (NSS) by focusing on two antecedents of negotiation success. On the one hand, we argue that NSS should stimulate a common (cultural) identity among the individual negotiators, a strong predictor of integrative agreements in prior research. On the other hand, NSS should seek to provide information in order to develop shared cognition among negotiators. Negotiators' perceptions of the problem at hand and possible solutions often diverge significantly as a consequence of their different knowledge and motives. In this article, we report some experimental support for this framework. We conclude that shared identity and shared cognition are relatively powerful predictors of outcomes of international negotiations, and that minimal variations in the configuration of an NSS can have strong effects on these results.