This article maps the prospects of crowd-sourcing technologies in the area of corruption reporting. Despite a flurry of initiatives and media hype in this area leading to hopes of an effective tackling of corruption, the potential of crowd-sourcing has so far been mainly approached from a technology-centric perspective. Where challenges are identified and worked on they are primarily technical and managerial in nature, such as challenges of privacy protection, data management, information validation and fundraising. However, little attention has been paid to insights from a growing body of multi-disciplinary literature on how corruption works, how it can be tackled, and more generally how observed logics of collective action and social mobilization interact with technological affordances to condition the success of these efforts. Linking the technology-centric experience of crowd-sourcing more closely to our evolving understanding of corruption makes it possible to move beyond common-sense conjectures in this area, to identify some little-discussed challenges, and develop some fresh ideas around the future of crowd-sourcing corruption.