The growing literature on the critical success factors (CSFs) of the public-private partnership (PPP) projects mostly focus on one or a couple countries generally from several Asian economies or developed countries. This study, on the other hand, analyzes a large sample of Islamic countries (many of which remained untouched before) from Middle East and North Africa, Sub-Saharan Africa, and Asia. Based on a sample of 36 transport experts working in the government from 25 Islamic countries, this paper employs a questionnaire survey to evaluate how they assess the CSFs in the transport PPP projects. According to the responses to the questionnaires, financial strength of the private partner, political support, political stability, effective monitoring of the private partner, and favorable legal framework are the top five CSFs. In addition, our complementary factor analysis groups 18 CSFs into five factor groupings such as (i) transparent and competitive bidding, (ii) financial strength and stability, (iii) effective relationships between public and private parties, (iv) financial markets and risk management, and (v) public and political support. The findings reported can help policy makers better design the PPP procedures, reduce the associated risks, and ensure value for money.