Most countries that have adopted the public–private partnership (PPP) model as a means of implementing infrastructure projects have launched dedicated supporting units to guide policy development and stimulate project implementation. This paper draws on the theoretical notion of PPP-enabling fields to carry out a comparative analysis of the roles and functions of PPP-supporting units across 19 European countries with varying PPP experiences. We distinguish four categories of national support of PPPs, from skeptical systems of zero support to full-fledged PPP systems. Furthermore, we take initial steps to analyze the possible link between national differences in institutionalized PPP support and the amount of implemented PPP projects. Finally, pathways for further research on PPP-supporting units are discussed.