The Steyr TMP is a modern compact sub machine gun. This short-sized SMG came out of the same military concerns that repeatedly led the U.S. Infantry School to start a new approach to the Personal Defense Weapon (PDW). These concerns are shared by most modern armies and arose from the poor efficiency of the semi-auto pistol when used under true combat conditions as a last ditch defense weapon, especially by those people whose primary task is not combat. Keeping in mind the main functions of the possible users, they fixed their eyes on a lightweight and compact PDW system which also had to provide firepower and to be easily controllable by a non-expert shooter. This system had to give the same firepower as a submachine gun, while having a pistol-type weight and length.

It is blowback operated, locked breech design, with rotating barrel. both upper and lower receiver are made from polymer. This mean that after the shot bolt with barrel locked to it are moving backward for some 4 millimeters, then the barrel rotates clockwise slightly, and thus unlocks the bolt. Rotation is controled via a small cam on the barrel that follows the spiral groove inside the receiver. The Austrian weapon differs from conventional machine pistols in its very tight structure. The moving parts are enclosed in the upper receiver, of which the ejection port is sealed by the breech assembly in its forward position, thus protecting the mechanism against external dirt and water. The trigger group, the hammer unit and the safety devices are seated in the lower receiver, which is held together with the upper receiver by a sliding lock and located above the front grip; it allows a fast field stripping.

The TMP has selective fire capability that in full-auto carries a cyclic rate of 900 rpm. Available only to military, police and other official entities, the TMP is finding favour among professionals in the field of VIP protection, given its overall fine quality while retaining qualities such as compact size, controllability, high firepower, instinctive aiming and accuracy within its designed range.