The research aim is to develop and apply the conceptual inter-organizational knowledge transfer effectiveness (IOKTE) model to the inter-organizational transfer of Public-Private Partnership (PPP) related knowledge between public sector organizations in Flanders. The model assumes a relationship between an individual's ability to make PPP-related decisions and the extent to which knowledge is sought after, applied and shared in an inter-organisational manner within the public sector. The inter-organizational transfer of knowledge studied in this article is specific to PPP in Flanders and studied for public sector actors active at diverse policy levels. The aim is to uncover the extent to which the current system of inter-organizational knowledge transfer fits the user's satisfaction, expressed as the extent to which the use of the system improves the perceived decision-making on PPPs. The results indicate that searching for, sharing and using PPP-related knowledge sourced in public sector organizations improve the perceived decision-making ability. The research establishes that the current public sector PPP knowledge transfer system is perceived as being effective, yet for the assessment of its efficiency, insufficient data is found. Issues that stand to be improved are the fragmentation of the knowledge assets and the access across policy levels.