For a sustainable diet, especially with regard to animal welfare, human health, and environmental issues, a significant reduction in the consumption of animal source foods is essential. The most frequently reported motivations for a meat-reduced or meat-free diet are ethical concerns about animal welfare. This study realizes one of the first consumer segmentations in the context of the human–animal relationship based on domain-specific values; animal ethics. Such a consumer segmentation is relatively stable over time and encompasses the issue of the human–animal relationship in its entirety without limiting itself to a specific question. Based on a comprehensive consumer survey in Germany and by means of a three-step cluster analysis, five consumer segments characterized by different animal-ethical value profiles were defined. A subsequent analysis revealed a link between animal ethics and diet. As a key result, relationism as an animal-ethical position seems to play a key role in the choice of a sustainable diet. About a quarter of the population is characterized by a combination of animal welfare-oriented ethical positions with a clear rejection of relationism, i.e., they do not distinguish between farm animals and companion animals. This specific combination of animal-ethical values is associated with a significantly above-average proportion of flexitarians and vegetarians. Thus, the study contributes to a deeper understanding of existing animal-ethical values and their link to the choice of diet.