In modern environmental education, for a sustainable environmental management, the most frequently emphasized ethical justification is the moral responsibility of the current generation to future generations. Even though this approach directs people to protect the environment for future generations, the responsibility is indirect. This is because the environment is placed in a position that is respected not for itself but for the benefit of future generations. However, for religions, all existence deserves existential respect because it is divine in origin. It is therefore important to consider these religious theories in religious education for the development of sustainable environmental awareness. The curricula of Religious Culture and Ethics Knowledge course has been changed four times in 1982, 2000, 2006 and 2018. In this context, this chapter aims to explore how sustainable environmental education has been evaluated in Religious Culture and Ethics Knowledge’s curricula and textbooks since 1982, as religious education has a potential to contribute significantly to sustainable environmental awareness. Moreover, it intends to make suggestions in line with better sustainable environmental education for future curriculum development and preparation of textbooks in schools’ religious education. It is understood that these curricula held the issue in the aims, values, achievements and units in different shapes and forms.