This chapter introduces the principle of shape memory function in polymers and classifies shape memory polymers according to their molecular structures, trigger patterns and applications based on a literature review. One of the novel functional shape memory polymers with substrate bonding antibacterial activity is detailed and a new design of supramolecular shape memory polymers is discussed. Finally, shape memory fibres are introduced in comparison with other existing man-made fibres to clarify the uniqueness of such smart textile materials.