Public-private development partnership constitutes the core of a deepening normative agenda that places private actors as active development agents and as means through which other development objectives are pursued in partnership with publicly funded aid actors. This normative agenda may challenge international development. This article goes beyond the official policy level to explore the formation of public-private development cooperation in practice, not just on paper. It zooms into the partnership between a Norwegian NGO and a multinational company and their joint project to renovate an old vocational college in Ethiopia to serve the private actor's need for qualified workers. The article shows how a publicly funded development project becomes a proxy for private interests, but argues that the diversion of public aid is not due to bad intentions or conflicting interests. Rather, it is the result of interface situations created by the public-private partnership agenda and its intentional merger of actors with distinct institutional logics, accountabilities and rationales. The article demonstrates how actors put together as part of the public-private partnership agenda end up undermining the agenda itself because of the interface situations created in the nexus of public and private actors.