This chapter aims to portray the concepts of green chemistry (GC) and sustainable chemistry (SC) with regard to the textile sector and in response to the increasing challenges of the sector in terms of sustainability. It highlights potentials and pitfalls and offers concrete examples and practices of SC relevant for the textile industry. The textile sector is one of the most polluting industries in the world, contributing 20% to total industrial pollution of the water resources. In total, 5 billion kg of dyes, pigments and finishing chemicals are currently in use in the textile industry, adding up to more than 8000 different chemicals utilized for garment production. Moreover, extensive resource use (e.g., fossil fuels, processing chemicals, water etc.) in combination with unhealthy, exploitative working conditions pose a myriad of challenges involving all dimensions of sustainability. Once introduced into a process or product, chemicals and their products of unwanted side reactions and of incomplete mineralization in effluent treatment, so-called transformation products (TPs), are likely to remain a concern throughout the product’s lifecycle and even beyond. For example, textiles at their life’s end, so-called post-consumer textiles, still contain up to 90% of the chemicals that were initially introduced during manufacturing or finishing. This high amount of chemical residues on textiles (only partly washed out during laundry) is not only problematic in terms of resource use, but it is also an environmental threat. Residues are continuously released due to limitations in conventional wastewater treatment and form waste and dump sites affecting human health and well-being. The aforementioned sustainability issues arising during textile production, distribution, use and disposal are inextricably linked to societal and cultural systems. The complex, dynamic and highly intertwined nature of these sustainability challenges in the textile sector calls for both a focus on input prevention of chemicals and a strong normative premise of intentionally beneficial design of chemicals that are not harmful to the environment and human health. Sustainable chemistry has become an emerging concept in response to various sustainability challenges associated with the production, distribution, use and discharge of chemicals and products. It has been acknowledged by UNEP as an important cornerstone in achieving the Sustainable Development Goals (SDGs) and servers as a core concept within the Global Chemical Outlook II. Whilst green chemistry mainly addresses the synthesis of chemicals and some of their properties, SC reaches beyond the disciplinary boundaries of chemicals and their usage by a systems thinking approach. Being both a path and a goal, SC can act a beneficial umbrella concept for addressing the highly complex sustainability challenges regarding chemicals in the textile sector. Its specific potentials for the textile sector have not been studied hitherto and lie in its focus on input prevention, which influences not only production or wet processing of textiles, but the entire supply chain—including up- and downstream users—even beyond the product’s end of life. Practiced of SC within the textile industry addresses spatial as well as temporal scales, flows and dynamics of chemicals, materials and products and hence addresses drivers of highly complex and currently unsustainable practices. Specific examples and practices of SC within the textile sector will be described in-depth such as new business models (e.g. chemical leasing).