The All Terrain Personal Transport (AT-PT) was an experimental one-man walker originally designed by the Old Republic. This two-legged walker stands nearly three meters tall and was designed to turn a single soldier into an armed force that could stop a full squad of opponents. Ultimately, the AT-PT project was cancelled, although Imperial engineers later used many of it's concepts when they created the AT-AT and AT-ST.

The AT-PT was intended to be a major component of the Republic's ground forces. AT-PTs cannot match the speed of repulsorcraft, but they can be devastating against conventional ground forces. Project designers developed the vehicle to be suitable for open ground, shallow water, jungle, mountain terrain, and urban areas. The independently adjusting leg suspension system allows the walker to scramble over inclines and obstacles that block repulsorlift and treaded vehicles.

The AT-PT features a central command pod and two side-mounted legs. The legs can be fully extended upward for high speed movement or to give the driver a better observation position. In cramped conditions, the AT-PT moves in a "half-crouch," with the command pod lowered to be even with the legs' drive joints. This drive system gives the light walker superior balance compared with the larger AT-ST. The AT-PT can reach a top speed of sixty kilometers per hour in open terrain, and its drive unit can handle up to forty-five-degree inclines.

The command pod is heavily armored, giving the driver outstanding protection. Entered from small side hatches, the cramped cockpit is designed for a single driver, but in an emergency an extra passenger can be carried. When sealed, the craft is virtually impenetrable by small-arms fire. The pod has a primitive sensor system for navigation. In addition to the cramped pilot compartment, the command pod holds the weapons systems and the main drive unit. Standard weaponry for an AT-PT includes a twin blaster cannon and a concussion grenade launcher.

The Republic planned to assign platoons of soldiers to AT-PTs, thus giving a single platoon the firepower of nearly a company of ground soldiers: AT-PT platoons were to be equivalent to light mechanized infantry units, but at a substantially reduced price. And, with the speed of the AT-PTs, plus their extended comlink ranges, the platoon could patrol a far larger area than could comparable ground forces.

AT-PTs were never given the thorough battlefield testing they deserved. The majority of the Republic's AT-PTs were stored aboard the Katana Dreadnaughts: when those ships disappeared, momentum for furthering the AT-PT project vanished. AT-PTs were rediscovered when the New Republic forces found the lost Katana fleet. While aboard one of those Dreadnaughts, Luke Skywalker and Han Solo used an AT-PT to fend off Grand Admiral Thrawn's clone stormtroopers, thus beginning a new chapter in the history of the All Terrain Personal Transport.