The Gravettian site of Předmostí I in the central Moravian Plain has yielded a rich and diverse large mammal fauna dated around 25–27,000 14C years BP (ca. 29,500–31,500 cal BP). This fauna includes numerous carnivores (cave lion, wolf, brown bear, polar fox, wolverine) and herbivores (reindeer, large bovine, red deer, muskox, horse, woolly rhinoceros, woolly mammoth) whose trophic position could be reconstructed using stable isotopic tracking (δ13C, δ15N, δ34S) of bone collagen (n = 63). Among large canids, two morphotypes, “Pleistocene wolves” and “Palaeolithic dogs”, were considered, and two human bones attributed to the Gravettian assemblage of Předmostí I were also sampled. The trophic system around the Gravettian settlement of Předmostí I showed the typical niche partitioning among herbivores and carnivores seen in other mammoth-steppe contexts. The contribution of the analyzed prey species to the diet of the predators, including humans, was evaluated using a Bayesian mixing model (SIAR). Lions included great amounts of reindeer/muskox and possibly bison in their diet, while Pleistocene wolves were more focused on horse and possibly mammoth. Strong reliance on mammoth meat was found for the human of the site, similarly to previously analyzed individuals from other Gravettian sites in Moravia. Interestingly, the large canids interpreted as “Palaeolithic dogs” had a high proportion of reindeer/muskox in their diet, while consumption of mammoth would be expected from the availability of this prey especially in case of close interaction with humans. The peculiar isotopic composition of the Palaeolithic dogs of Předmostí I may indicate some control of their dietary intake by Gravettian people, who could have use them more for transportation than hunting purpose.