“Most research on Public–Private Partnerships (PPPs) in infrastructure development focuses on phases prior to construction. The implementation phase itself has received less attention. However, sound public–private agreements and project preparations can fail during project implementation because of, for example, unforeseen events and ineffective responses to them. We conducted case studies on two infrastructure projects to examine which management responses to events during implementation produce (un)satisfactory outcomes. We found that externally oriented responses or a cooperative stance between the public and private partners produce satisfactory outcomes in responding to events. In practice, however, management responses are often internally oriented and non-cooperative, resulting in unsatisfactory outcomes. We identified three explanations for this, related to time pressure in implementation, the organization of the involvement of external stakeholders, and project culture in the PPP. The article concludes with implications for management and policy of infrastructure PPPs.”