Current literature provides a deep understanding of firms’ vertical relationships, but knowledge of horizontal relationships among firms that occupy similar positions along a supply chain is rather limited. The main purpose of this chapter is to explicate issues related to cooperation among competitors, or ‘coopetition’. This chapter provides a broad overview of the major facets of coopetition. It seeks to increase awareness of this important strategic option among managers who plan to develop inter-firm collaborative relationships and to provoke further discussion and investigation of this phenomenon among marketing scholars.