To avoid impasses and to reach mutually beneficial agreements in negotiation and mediation, parties need to overcome a multitude of pitfalls—both of psychological and structural nature. En route to facilitating beneficial agreements, mediators can build on negotiation theory, which provides a number of key insights into the psychological and structural backdrop of conflicts. Capitalizing on these insights may alter parties’ willingness to concede, their problem-solving behavior, and their ability to discover hidden resources. In this chapter, we review some influential theories, models, and concepts from the field of negotiation research and illustrate how these can help to better understand the pitfalls of workplace conflicts. We furthermore discuss a number of implications that negotiation theory has for successful mediation in the workplace.