In the 1960s, Seyyed Hossein Nasr was the first to articulate in contemporary language the vision of an Islamic environmentalism. Ever since, in a number of articles and interviews Nasr has elaborated his vision further. As the ultimate solution to the environmental crisis, he has persistently argued the need to substitute the prevalent scientific worldview with a religious worldview. However, there has not been any systematic and comprehensive presentation of Nasr’s approach that discusses his ideas in the context of the intellectual currents which have shaped his thought. This thesis attempts to address the gaps in the presentation of Nasr’s religious perspectives on environmentalism. The research has been guided by two questions: 1) what do we need to know to best appreciate Nasr’s vision? And 2) how does Nasr’s vision adhere to traditional Islamic thought? The thesis has demonstrated that Nasr’s arguments are rooted in metaphysical principles of reality, found in the perennial philosophy as well as in traditional Islamic metaphysics, Sufism, philosophy and sciences, as represented by the key authorities of those areas. The thesis hopefully contributes to scholarship in an important dimension of Islamic environmentalism and on the environmental aspects of the relevant intellectual currents.