The “environment” and “justice” of environmental justice are often defined through Western ways of thinking. Empirical environmental justice research, however, increasingly takes place in the context of the global South. As a result, there is a tendency to transpose Western concepts and frameworks to the global South, running the risk of being ineffective and of producing additional injustices. Drawing on decolonial thought, a Latin American and Caribbean theoretical movement, this paper analyses the problems which arise when Western concepts are used as the main organizing principles of non-Western environmental justice movements. Examples include failing to account for cases involving mutually undermining modes of life, hence presenting deliberate exposure to environmental harm as a fair solution; rendering invisible the fact that “participation” may contribute to the reproduction of environmental injustices, sometimes with the consent of those who are likely to be the first victims of environmental injustices; or reproducing the idea that communities in the global South do not produce knowledge, that their knowledge is inferior, or only useful for empirical observation, while Western science provides for the underlying theoretical framework. We conclude by highlighting some of the principles of a decolonial environmental justice.