This presentation introduces smart textiles, which integrate microelectronics into textiles to endow them with new active properties. Smart textiles can be classified as passive, active, or ultra smart depending on their sensing and reactive capabilities. Key functions of smart textiles include sensing environmental stimuli, processing sensor data, actuating responses, storing energy, and enabling communication. Examples of smart materials discussed are thermo-regulating, chromic, luminescent, conductive, and electronic textiles. The presentation provides examples of how these materials are incorporated into and change the properties of textiles.