Following the Green Revolution, conventional, ‘scientific’ plant-breeding quickly became the dominant breeding paradigm. However, conventional breeding has failed some farmers, particularly those in marginal agricultural environments. This conventional approach has been increasingly challenged by more collaborative approaches to breeding which bring farmers, scientists, extension officers and other actors together in decision-making. These approaches are commonly referred to as participatory plant breeding and participatory varietal selection. Such participatory approaches to plant breeding offer opportunities to better involve farmers and communities in the breeding process and to better target and meet their needs. This chapter will review and discuss, with the help of case studies from all over the world, both the principles of participatory plant breeding and participatory varietal selection, as well as the advantages and disadvantage of the participatory approach compared to the conventional approach to plant breeding.