This paper seeks to contribute to the ongoing debate concerning the role of collaborative public-private relationships in fostering innovation in public procurement. We focus on a particular form of public procurement that relies on the collaboration between the private and the public sector, namely the public-private partnerships (PPPs). In particular, the paper aims at overcoming limitations of the existing literature on PPPs by providing answers to the following key research questions: Which are the PPP features that favor innovation? How properly structure a PPP in order to foster innovation? Drawing upon the main streams of studies on innovation, we develop a conceptual framework theoretical framework on the relationship between PPP and formulates the research hypotheses. An econometric analysis is then applied to empirically test the hypotheses. The developed framework identifies the relations existing between each PPP feature and the level of innovation. Specifically, we find that a wider involvement of the private sector will increase the level of innovation. The market concentration seems to be positively correlated to the innovation. As for the contract structure, repayment mechanisms based on performance favour innovation in PPPs, whereas the existence of risk-sharing mechanisms in the contract decreases the likelihood that some innovative activity related to the PPP project occurs. Finally, in relation to the network structure, we found no significant effect on innovation. The contribution of our research is twofold. First, we contribute to fill the gap in the academic literature on PPP and innovation by proving whether and in which conditions the PPP model is capable of developing innovative solutions. Second, we contribute to the practice by defining how PPP features have to be structured in order to foster innovation, thus providing meaningful guidelines to those called to structure these arrangements.