The Segway PT is a two-wheeled, self-balancing electric transportation device invented by Dean Kamen and unveiled in December 2001. It is produced by Segway Inc. of New Hampshire. The name "Segway" is a homophone of "segue" (a smooth transition, literally Italian for "follows"). PT is an initialism for personal transporter while the old acronym HT was an initialism for human transporter.

Computers and motors in the base of the device keep the Segway PT upright when powered on with balancing enabled. Users lean forward to go forward, lean back to go backward, and turn by using a "Lean Steer" handlebar, leaning it left or right. Earlier HTs used a twist grip to steer by twisting the grip left and right. Segway PTs are driven by electric motors at up to 5.6 m/s (12.5 mph/20 km/h). Gyroscopic sensors (see vibrating structure gyroscope) are used to detect tilting of the device which indicates a departure from perfect balance. Motors driving the wheels are commanded as needed to bring the PT back into balance.

In laws that regulate it, the applicable category is sometimes called "electric personal assistive mobility device" (EPAMD). A niche that Segways have been often adopted into is transportation across military bases, warehouses, corporate campuses or industrial sites, or neighborhoods in place of walking or bicycles.