This paper reviews the research agenda lineage on public-private partnerships (PPPs) from Broadbent and Laughlin's seminal piece in 1999. The PPP phenomenon is viewed at five levels: project delivery, organisational form, policy, governance tool and as a phenomenon within a broader historical and cultural context. We argue that whilst a variety of research issues will continue to be relevant, five corresponding areas deserve future visibility for a renewed research agenda: (1) Financialisation of PPPs, (2) global PPP market actors, (3) internationalisation of policy on PPPs, (4) long-term complex contracts as a governing regime and (5) PPPs in BRICS and developing countries.