It is difficult to argue that an explicit jus cogens norm on the protection of the environment exists at the international level. As it is known, jus cogens norms protect the fundamental values of the international community, are ‘hierarchically superior’ to other international law norms and universally applicable (A/CN.4/L.936, ILC). Does the right to environment have the potential to be recognised as a jus cogens norm? This paper argues, following the legal reasoning followed in the advisory opinion of the Inter-American Court of Human Rights of 2007, that the right to a healthy environment is gradually consolidating at the international level as jus cogens norm. Jus cogens has developed as humans-related norms, but in recent years it has become more and more clear that the protection of the environment cannot only serve human interests but must serve the interests of every human and non-human beings, and of ecosystems as well.