While differentialists deny that non-linguistic animals can have a sense of justice, assimilationists credit some animals with such an advanced moral attitude. We approach this debate from a philosophical perspective. First, we outline the history of the notion of justice in philosophy and how various facets of that notion play a role in contemporary empirical investigations of justice among humans. On this basis, we develop a scheme for the elements of justice-relevant situations and for criteria of justice that should be (...) fruitful in studying both humans and animals. Furthermore, we investigate the conceptual connections between a sense of justice, on the one hand, and various other mental powers, on the other, and indicate which of the latter may be beyond the ken of animals. Next, we consider recent empirical research on justicerelated phenomena in animals. We argue for an intermediate position: While animals can at least in principle satisfy some preconditions of justice (intentional action, rulefollowing), others are problematic, notably possessing a notion of desert. A space for justice in social animals exists, yet it is rather limited compared to the rich cultures of justice in humans. Finally, we reflect on some actual or alleged implications of research on animal justice. As regards justice in humans, one should avoid a simplistic image of ‘‘natural justice’’ as boiling down to equal allocation of goods. As regards justice for animals, one should be weary of the contractualist assumption that only those capable of justice themselves are deserving of ‘‘just’’ treatment. (shrink)