Environmental justice theory appears, questioning the ethical duties of humans towards other species, and Nature’s rights. Environmental justice moves away from the anthropocentrism, which leads development theory, and uses Ecocentrism instead. By the virtue of this new paradigm, man ceases to be the center of the world, and is thought to be just one of the many elements in Nature. From this viewpoint, all species and their lives are creditors of respect. This text will analyze each of the principles of this new theory, which was introduced mainly by Christopher Stone and which is inspired of autochthones views. We will also carry out an applied study of this approach in various legal systems that have already opened the way to a change of paradigm: Ecuador, Bolivia, New Zealand, India and Colombia. Finally, we will highlight the complexity, but also the importance of institutionalizing a new paradigm that allows the emergence of a real environmental justice.