Farmer-to-farmer extension (FFE) has received considerable interest in developing countries due to a decline in government extension services. There are, however, questions as to how FFE can be improved to enhance effectiveness and sustainability of the approach. One area that may hold the key is to understand volunteer farmer-trainer (VFT) motivations. Informal and formal interviews were held with VFTs in a smallholder dairy development project in Kenya, Uganda and Rwanda. Data were collected on the reasons why VFTs became trainers and why they continue to train. Findings of the study showed that VFTs were motivated by a combination of intrinsic and extrinsic factors. These factors are not static; they change over time. Gaining knowledge and skills as well as altruism were found to be the most important motivating factors for becoming trainers in the three countries. However, a few years after becoming trainers, income earned from selling inputs and specialized services associated with training was an important motivating factor to VFTs in Kenya. In Uganda gaining knowledge and skills remained the most important whereas in Rwanda, a new motivation, increased demand for training, was the most important reason for continuing to train. These findings point to the fact that the general reasons that motivate VFTs irrespective of context are similar; however, the importance attached to motivations is context specific. These motivations can provide insights into which incentives can be enhanced to improve effectiveness and sustainability of FFE.Keywords: farmer-to-farmer extension; volunteer farmer trainers; fodder innovations; East Africa; motivation; sustainability Introduction Following the decline of government extension services in developing countries, low-cost community-based extension approaches have been developed to deliver technologies, help empower farmers to improve their capacities and, in addition, facilitate farmers to organize themselves for service provision and marketing (David, 2007). These extension approaches are demand driven, client oriented, cost effective and efficient (Kiptot & Franzel, 2014;Lukuyu, Place, Franzel, & Kiptot, 2012;Wellard, Rafanomezana, Nyirenda, Okotel, & Subbey, 2013). Farmers are placed at the centre of knowledge generation and dissemination processes. These approaches work on the assumption that farmers have the ability to spread innovations effectively due to their local knowledge, use of the local # 2016 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group 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. * Corresponding author. Email: e.kiptot@cgiar.org International Journal of Agricultural Sustainability, 2016 Vol. 14, No....