This study explores the incorporation of Green Pedagogy into English language instruction as a strategic pedagogy for environmental awareness development and sustainable development. English, as the world’s lingua franca, is a major driver of climate debate, science publication of research papers, and global environmental policy-making, and is therefore well positioned to be leveraged to promote global causes of sustainability. The study develops a conceptual framework incorporating English Language Teaching (ELT), environmental education, and sustainability impacts, using theories of Content and Language Integrated Learning (CLIL), ecological literacy, and transformative learning. On the basis of conceptual synthesis and case study analysis, the paper demonstrates how sustainability issues can be mainstreamed in ELT using vocabulary development, critical discourse analysis, and project work. The proposed Green Pedagogy framework encourages critical thinking, relevance to real life, and global citizenship without sacrificing essential language learning outcomes. By integrating English instruction with the United Nations Sustainable Development Goals SDG 4 (Quality Education) and SDG 13 (Climate Action), this study addresses a critical void in language pedagogy. It offers pedagogical approaches and practical tools of application for language teachers and policymakers to mainstream sustainability meaningfully in language education.