Triboelectric nanogenerator (TENG), an emerging energy conversion technology, offers innovative pathways for energy harvesting and self-powered sensing. To achieve superior performance, researchers commonly employ substantial quantities of original or treated polymers, resulting in high energy and precise sensing. Nevertheless, the sustainable development of TENGs faces significant challenges related to environmental compatibility, pollution hazards, and high production and disposal costs. To address this issue, numerous green materials for diverse TENGs are introduced and advanced. These materials may encompass natural resources, household waste, and recyclable materials, among others. Consequently, a review of the progress in TENGs based on green materials, which can be called green TENGs, becomes imperative to advance its sustainable development. To this end, this work comprehensively elucidates the development of green TENGs from the perspective of materials processing and treatment degree for the first time. Various green TENGs, including food waste, discarded daily-use items, plant organs, biodegradable industrial products, and natural cellulose, are meticulously categorized. This review not only systematically synthesizes the latest research advancements in green TENGs, but also offers insight into their processing methodologies, working characteristics, and potential application scenarios. Finally, it envisions the challenges, proposed solutions, and future research directions for the development of green TENGs.