Leveraging open source practices provides value to businesses when entrepreneurs and managers understand how to collaborate effectively in an open source ecosystem. However, the complex mix of different actors and varying barriers to effective collaboration in the ecosystem pose a substantial challenge. How can a business create and capture value if it depends on effective collaboration among these different groups? In this article, we review the published research on open source collaboration and reveal insights that will be beneficial to entrepreneurs and managers. We organize the published research into four streams based upon the following actor groups: i) governance actors, ii) competitors, iii) complementors, and iv) the core community. Then, through induction and synthesis, we identify barriers to collaboration, first by ecosystem and then by actor group. Finally, we offer six recommendations for identifying and overcoming barriers to collaboration in an open source ecosystem.