"Management of complexity" was identified as a paradigm for negotiation analysis 25 years ago. Substantial progress has been made in conceptualizing complex negotiations since, although less has been accomplished with regard to operationalizing that knowledge so that tools can be developed to manage complex negotiations. This article begins by reviewing five separate theoretical frameworks of negotiation complexity and, through this analysis, identifies six significant characteristics of negotiation complexity: Party numbers, negotiator roles, external environment, negotiation process, negotiation strategy, and party relations. Operational tools are identified for each variable. On the basis of this analysis, the article concludes by identifying additional tools that could be developed for managing complex negotiations.