This study investigates and ranks the critical capacity building challenges (CBC) impacting the Tanzanian public–private partnerships (PPPs) projects. The strength of interactions between CBC is established, with practical solution proposals offered and benchmarked with previous studies. A total of 8 CBC were identified from a scoping review. Data was then collected from 81 PPP practitioners, and subjected to descriptive and inferential statistics. The results demonstrated a disparity of ranking of the 8 CBC among those with and without PPP experience, with the most highly ranked 4 CBC identified as ‘limited local people with experience’, ‘lack of resources’; ‘lack of successful PPP projects’, and ‘lack of permanent PPP trainers’. The least ranked was ‘lack of political will for promoting PPPs’. Strong and positive correlation between ‘inadequate qualifications’ and ‘lack of hands-on training’ was established. Suggested solutions were broadly classified in the following four categories: (1) Training and education; (2) Benchmarking and lessons learnt; (3) Knowledge transfer and experience sharing; and (4) Institutional reforms; and supportive enabling environments. The results of this study foster better understanding of the facets of capacity building, provides PPP stakeholders with solutions for mitigating and addressing the challenges during the PPP project lifecycle.