Abstract Purpose- The success of any public-private partnership (PPP) project is largely dependent on the country’s maturity on critical success factors (CSFs) that made PPP projects successful. Thus, the identification of metrics and standards for measuring the maturity of stakeholder organisations on CSFs for PPP projects implementation remain a challenge. Therefore, the purpose of this study is to use CSFs to develop a process maturity and determine the current maturity levels of stakeholder organisations in PPP projects implementation in Nigeria. Design/methodology/approach- The study adopted literature review and six PPP project case studies including interviews in each case study and expert forum. The outcome of a comprehensive literature review provides a total list of fourteen CSFs that made PPP projects successful in Nigeria. These CSFs were employed for capability maturity levels definition ranging from level 1(Ad hoc) to level 5(Optimizing) in line with Capability Maturity Model (CMM) concept. Quantitative assessment was considered as a support tool for making an overall assessment of both the public and private organisations current capability maturity levels and for comparison approach. Findings- A capability enhancement framework for stakeholder organisations in PPP project was developed. This framework was employed in assessing the current capability maturity levels of stakeholder organisations involved in PPP projects in Nigeria. Using this framework, it was found that public sector organisations were positioned between maturity level 1 and maturity level 2 (out of 5 maturity levels) on CSFs applicable to them. While most private sector organisations were placed in maturity level 2 on CSFs associated with them. Practical implication: The results emanated from this study provided both the theoretical and practical implications. The theoretical implication provides new insights into the usefulness of CSFs in PPP projects and indicates that merely identifying possible CSFs for PPP projects are not sufficient. The practical implication shows that the framework developed in this study had provided the benchmark for the identification of methodical approach, and standard to process improvement in PPP infrastructure projects, which can be replicated in both the developed and developing countries. Thus, the framework could be used to benchmark future studies. Originality/value- The framework would provide a useful guide and roadmaps for improvement by indicating ‘what’ needs to be done by stakeholder organisations involved in PPP projects in achieving higher capability maturity levels on identified CSFs for PPP projects in Nigeria and developing countries at large.