The principle of sustainability aims for the protection of ecological systems and their integrity. Its subject matter is ecological processes. However, social processes determine to what extent and how ecological systems should be sustained. This way sustainability becomes a social issue. As there are choices to be made between competing needs and wants, questions of distributive justice arise. How sustainability affects the idea of justice will be explored in this chapter. The argument is that conventional theories of justice have been insufficient to conceptualize the environmental dimension of justice. Following recent ethical advancements, the concept of ecological justice will be developed. The notion of ecological justice is fairly new2 and not widely known among lawyers. This is in stark contrast to environmental justice, one of the most commonly used terms in the general environmental debate.3 What is the difference between these aspects of justice and why is ecological justice important for environmental law? Generally understood conceptions of ‘justice’ are concerned with fair distribution of social goods and burdens. Distributional concerns are at the centre of most theories of justice. They are also at the centre of justice theories with respect to environmental protection. However, there are two different relational aspects to be considered here: the justice of the distribution of the environment among people, and the justice of the relationship between humans and the rest of the natural world.