This chapter explores the integration of environmental education and the zero waste approach with metacognitive awareness, reasoning skills, and the Technological Pedagogical Content Knowledge (TPACK) framework. It begins by presenting the conceptual foundations of environmental education, emphasizing the need to develop environmental ethics and sustainability-oriented behaviors in response to ongoing ecological crises.  Informal learning environments such as nature-based activities, ecological site visits, and science museums are highlighted as effective contexts for fostering metacognitive awareness, value-based learning, and student engagement in real-world environmental challenges. Furthermore, the chapter discusses the critical role of reasoning in enabling students to analyze environmental issues through inductive, deductive, causal, and ethical lenses. These reasoning skills are essential for cultivating critical thinking, scientific inquiry, and responsible decision-making. The TPACK model is introduced as a powerful framework for equipping teachers with the ability to design interdisciplinary and technology-integrated lessons that promote sustainability education. A sample learning activity, “My Zero Waste School,” illustrates how environmental, pedagogical, and technological knowledge can be synthesized to create active, inquiry-based learning experiences. Overall, the chapter emphasizes the importance of combining formal and informal learning environments, higher-order thinking skills, and digital pedagogies to empower future generations as environmentally responsible global citizens.