Negotiation or bargaining is a well-known procedure in multi-agent systems. In economics, the bargaining problem arises when there is some gain from some trade. The challenge is to divide the gain given that (i) there is a conflict of interest, and (ii) any agreement must be approved by all involved individuals. Each agent follows some strategy in negotiation. The negotiation strategies define the sequence of actions (usually offers, counteroffers, accept, or reject) that the agents take during the entire interaction. Moreover, the agents’ actions should be compatible with a particular negotiation protocol. Often, some information, e.g., about preferences, is available to the negotiating agents. However, if such information is not available, a negotiation procedure can be performed sequentially so that an intelligent agent learns to negotiate optimally over time. In this thesis, the goal is to study and analyze, also potentially develop, negotiation strategies under uncertainty about different factors that affect the negotiation, such as agents’ preferences.