The emergence of 4D printing technology is revolutionizing textile engineering by integrating traditional materials with advanced manufacturing techniques to produce smart textiles that can adapt dynamically to environmental stimuli. Unlike conventional 3D printing, which creates static objects, 4D printing allows textiles to change their shape, properties, and functions over time, responding to temperature, humidity, light, and magnetic fields. This adaptability is achieved through the use of responsive polymers, polymer nanocomposites, and nanotechnology, enabling fabrics to self-assemble, self-heal, and modify their characteristics in real time. Key 4D printing techniques—including fused deposition modeling, stereolithography, and multi-material printing—are utilized to fabricate these smart textiles, which find applications in healthcare, sports, defense, and fashion. Although challenges related to material complexity, durability, and production scalability exist, ongoing research aims to enhance the functionality and affordability of 4D-printed textiles, paving the way for innovative applications in various industries.