Play, especially in its social form, is an enigmatic and multifunctional behavior that is essential for the development and maintenance of a great variety of individual and social competences in many social species. Bonobos are recognized as one of the most playful species and they can be used as a model to evaluate the importance of social play at all ages, given that they play at high frequencies even as adults, thanks to their developmental delay. By summarizing what is known about play behavior in bonobos and in other primate species, this chapter sheds light on the importance of social play in scaffolding the socio-emotional and communicative competence of individuals. Results obtained on bonobos allow the strong links between play in adults and social tolerance, a connection that becomes evident also in other species, including our own, to be revealed. © Oxford University Press 2017.