This book constitutes the thoroughly refereed workshop proceedings of the 3rd International Workshop on Incentives, Overlays, and Economic Traffic Control, ETM 2010, held in Amsterdam, The Netherlands, in September 2010. The 6 revised full papers presented together with a keynote and 4 short papers were carefully reviewed and selected from 21 submissions. The major focus of the accepted papers is seen in the following topics such as economic management of traffic and its related economic implications; ETM mechanisms and technologies; ETM application scenarios, such as that of peer-to-peer applications, overlay networks, or virtual networks; application-layer traffic optimization (ALTO); and economically efficient bandwidth allocation.