Textile processing using supercritical carbon dioxide (scCO2) medium is gaining prominence due to benefits such as being a non-toxic, eco-friendly solvent with zero-liquid-discharge and facilitating easy dye recovery and recycling. Its status as an environmentally benign solvent offers significant advantages over traditional aqueous and solvent-based methods, as proven in polyester dyeing. Applications of scCO2 impregnation are diverse, encompassing the incorporation of pharmaceuticals, functional finishing agents, dyes and other active compounds into polymeric matrices and surface modifications. Though still limited, recent studies have expanded the potential of scCO2 in textile surface modification and functionalization. This has enabled the development of materials with properties such as antimicrobial activity, UV protection, antioxidant capability, drug-loading and improved dyeing efficiency while reducing water and chemical consumption. This chapter reviews key studies that utilize scCO2 for the development of functional textiles through surface modification and impregnation. Recent advances and developments in textile surface modification and functionalization using scCO2 are presented. The review aims to encourage further research into the use of scCO2 technology for developing advanced functional textile materials and promoting its application on an industrial scale.