The success or failure of a Public-Private Partnership (PPP) project depends on various factors. This study aims to identify and assess critical success factors (CSFs) for PPP infrastructure project implementation. By a comprehensive review of prior studies, this study managed six primary categories extracting from 42 CSFs, such as public sector cluster (8 factors), private sector cluster (11 factors), procurement process cluster (7 factors), risk management (4 factors), project information (10 factors), and external cluster (2 factors). A theoretical structural equation model was formulated to signify the impacts of these clusters for PPP infrastructure project implementation. The necessary data was collected through an investigation with 216 PPP infrastructure professionals and practitioners. The findings indicated that the clusters of private sector, project information, and procurement process were the most influential affecting the success of the implementation of PPP infrastructure projects. By adopting the recommended strategies, public sector, private sector, and stakeholders participating in a PPP infrastructure project will be in better understand the success factors for these projects. As a result, this can improve project implementation efficiency in order to achieve the project's objectives.