Advanced materials for 3D and 4D printing have been developed through the integration of nanotechnology with additive manufacturing. The use of nano polymers in printed structures allows for increased mechanical, thermal, electrical, and stimuli-responsive qualities, as well as environmental adaptability. Nano polymers are polymeric matrices that contain fillers on the nanoscale. Nanocomposites, biopolymers, and stimuli-responsive materials are some of the important classes covered, and their significance in cutting-edge fields including aerospace, biomedicine, smart clothing, and environmentally friendly packaging is emphasised. Adding nano polymers to 4D printing makes it far easier to change shapes and have them self-actuate in response to external stimuli. This chapter highlights the revolutionary possibilities of nano polymers for nextgen additive manufacturing in terms of intelligent, environmentally sustainable, and application-specific solutions.