Food sharing is a prosocial behavior consisting of the unresisted transfer of monopolizable food from a possessor to another individual (Feistner and McGrew 1989; Stevens and Gilby 2004). Despite the cost for donors (i.e., loss of the food), intraspecific food sharing occurs in various insects, fish, birds, and aquatic, terrestrial, and arboreal mammals (Liévin‐Bazin et al. 2019; Carter et al. 2020). By far, most food sharing is intraspecific, and takes place while possessors are in the process of eating. Here, we describe the remarkable case of a captive chimpanzee, Pan troglodytes, regularly dispensing food to another primate species (baboons, Papio hamadryas) in a neighboring enclosure. We discuss likely causes and functions of this interspecific altruistic act. Observations were made in Xi’an Qinling Wildlife Park, Shaanxi Province, China (34°02ʹ56.22″N, 108°51ʹ48.60″E), where two adult chimpanzees and a group of around 40-50 baboons lived in adjacent enclosures. The female chimpanzee (AiAi) was the elderly mother of the male (DuoDuo, or DD). At feeding times, AiAi usually ate near the door to the chimpanzees’ indoor area, and she almost never interacted with the baboon group. The baboon group consisted of two one-male units. We recorded behaviors using focal-animal sampling (for information about subjects and methods, see Supplementary Materials).