This article conceptualizes the vulnerability of the different stages of Public-Private Partnership (PPP) models for corruption against the backdrop of contract theory, principal-agent theory and transaction cost economics, and discusses potential control mechanisms. The article's contribution to the debate on PPPs is twofold: first, an issue widely neglected by the pertinent literature is conceptualized. Second, as these PPPs are used not only in developed countries whose legal order may shield them sufficiently, but also in developing countries, carving out the vulnerable points in PPP arrangements may enable decision makers to install appropriate control mechanisms, if need be on project level.