Abstract: Wearable textile-based piezoresistive sensors convert interfacial pressure generated by human–environment contact into resistance signals, showing great potential in physiological monitoring, motion recognition, and human–machine interaction. Compared with conventional rigid devices and polymer-based flexible sensors, textiles offer softness, breathability, deformability, and facile integration. Their rough fiber surfaces, multipoint yarn contacts, and hierarchical porous structures amplify pressure-induced changes in contact area and conductive network reconstruction. Firstly, it introduces the sensing mechanisms and basic structures of textile-based piezoresistive sensors. Then, it summarizes multiscale substrates, including fibers, yarns, and fabrics, together with sensing materials such as metals/MXenes, carbon-based materials, and conductive polymers, and discusses the fabrication of functional fiber/yarn sensing elements and surface functionalization of textile substrates. Recent applications in health monitoring, motion sensing, and human–machine interaction are further reviewed. Finally, key challenges involving conductive-interface durability, coordinated optimization of sensitivity, sensing range and linearity, multisource interference at complex human interfaces, thermal-wet comfort, scalable manufacturing, and standardized evaluation are discussed, with targeted strategies proposed to facilitate the transition from laboratory devices to long-term wearable smart textile systems.