This paper proposes a novel framework for analyzing collaborative innovation that captures both competition and cooperation among firms, and examines the impact of private appropriation through IP rights licensing on firms’ incentives to innovate and on the overall outcome. I show that when developing technology together firms compete and cooperate, and that the intensity of each force depends on their technological similarity and business model. To study the net effect of these forces in equilibrium, I focus on the standardization of mobile telecommunications technologies and use a novel dataset on the development of 3G and 4G standards to estimate my model. I show that enforcing royalty-free clauses reduces the participation and contributions of firms, delaying the completion of the initial release of 4G by almost one year beyond the almost 3 years it took to develop.