Pliocene papionin monkeys of Eurasia, such as Paradolichopithecus arvernensis, Procynocephalus subhimalayanus, and Macaca sp. indet. from Yushe, are large-bodied and interpreted as at least partly terrestrial. Terrestriality in primates has implications for the dietary items consumed. Dietary proclivities from the evaluation of pit and scratch counts under low-magnification (35×) were inferred to address whether the diets of these Eurasian papionins differ and whether they correspond to extant primates (Papio ursinus, n = 24, Pan troglodytes, n = 9, and Gorilla gorilla, n = 10), three Plio-Pleistocene southern African fossil papionins with known isotopic values (Parapapio broomi, n = 14; Papio robinsoni, n = 10; Theropithecus oswaldi danieli, n = 8), or a Pliocene bipedal hominin (Australopithecus africanus, n = 8). Macaca sp. indet. from Yushe most closely resembles Australopithecus africanus from South Africa, which is characterized by evidence of some hard-object feeding. Paradolichopithecus from Romania and to a lesser extent Procynocephalus from northern India also exhibit use-wear scars associated with the ingestion of grit possibly associated with the exploitation of corms and bulbs of CAM or C4 plants. The dental microwear signal of grassland foraging typical of such C4 grazers as Theropithecus oswaldi danieli does not characterize other Plio-Pleistocene papionins. Pliocene papionin diets converge with those of Australopithecus, suggesting that global climate cooling intensifying during the Pliocene may have led both early baboon-like monkeys and australopiths to increase consumption of nutrient-rich edible plant storage organs in these fragmented and partially open habitats of the temperate Old World.