Government of Uganda and its development partners are targeting farmer groups as the vehicle for agricultural development because of the potential role they could play in promoting value addition, market and credit access. However there is limited empirical evidence on what drives membership to these groups. Using the Uganda Census of Agriculture 2008/9 data, this study reveals low levels of membership both at individual and household levels, with marked differences in regional participation. The key policy variables found to influence participation in farmer group included education attainment, distance to extension service and quality of road infrastructure. Thus, increasing membership to farmer groups requires government and its development partners to target more resources towards less educated farmers and those who live far from extension workers. The use of the local language in publicity materials is also important in ensuring participation among the illiterate and the less educated. Overall, there is a need for concerted efforts by all institutions supporting groups to ensure that existing groups have improved access to agricultural technologies and noticeable outcomes are achieved so as to attract more farmers.