Established development organisations face a long-standing legitimacy crisis for not living up to the expectations once set. Meanwhile, thousands of small-scale, voluntary development organisations -referred to as Private Development Initiatives (PDIs) -have joined the field of international development. In this article, I examine the legitimacy of their acts from a local government perspective based on an analysis of four dimensions of legitimacy: regulatory, pragmatic, normative and cognitive legitimacy. The study took place in May 2017 in the Kenyan coastal county of Kwale. A range of government officials were interviewed on how they perceive the interventions of international development organisations in general, and Dutch PDIs in particular, and on their cooperation with these development actors. The study shows that, although many of these PDIs operate in areas that fall under the responsibility of the local government, most of them have a rather limited cooperation with the local government, putting their legitimacy in the eyes of local government officials at stake.This is an open access article distributed under the terms of the Creative Commons attribution-NonCommercial-Noderivatives license (http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited, and is not altered, transformed, or built upon in any way.