Trees, whether occurring in wild stands or in agricultural landscapes, play a key role in the livelihoods of smallholders in the tropics. This chapter discusses tropical tree domestication in agroforestry, summarizing the authors’ contribution to the development of new tree crops in the tropics using agroforestry techniques. Following an introduction, a section is then included on the principles and techniques of tropical tree domestication covering identification of species for domestication, selection of ‘plus trees’ and vegetative propagation methods. The authors then provide examples of key tree species that have been targeted for domestication in the Amazon Basin (Bactris gasipaes, Calycophyllum spruceanum, Guazuma crinita and Inga edulis) and the Congo Basin (Irvingia gabonensis, Irvingia wombolu, Dacryodes edulis, Ricinodendron heudelotii, Cola acuminata, Cola anomala, Cola nitida and Prunus africana). The chapter concludes with a case study on participatory domestication of Allanblackia floribunda, a high-value agroforestry tree species in Central Africa.