Multilateral development banks (MDBs) play a pivotal role in the financing of electricity-generation projects in developing countries, thus having a major impact on the emission pathways of these countries. While information about the MDBs’ investments is publicly available, it is dispersed and hard to compare. A comprehensive compilation of all MDBs’ power-generation investments over the years has been missing. To address this gap, here we assess power-generation financing by all ten relevant MDBs during 2006–2015, in different regions, and through different branches of the banks. The study assesses technology choices by compiling a bottom-up dataset drawing information from 841 projects and programmes. We find that MDBs financed a major portion of all power-generation growth in the developing world, with an increasing share of renewables. However, MDBs have ‘greened’ their portfolios to different extents, and the activities of their public- and private-sector branches differ substantially.