The Steyr M1912, also known as the Steyr-Hahn, is a semi-automatic pistol that was initially developed in 1911 by the Austrian firm Steyr Mannlicher. It was designed based on the mechanism of the Roth–Steyr M1907. However, despite being developed as the Model 1911, it was not immediately accepted into service. It wasn't until 1914 that the pistol was officially adopted as the M12 by the Austro-Hungarian Army. Consequently, it became the standard-issue military handgun during World War I, earning acclaim for its ruggedness and resilience in the harsh conditions of trench warfare.

Originally chambered for the 9mm Steyr round, the Steyr M1912 initially encountered delays in its service acceptance. While the Austrian Landwehr received this handgun, other common army units were equipped with Roth–Steyr M1907 handguns and Rast & Gasser M1898 revolvers. Nevertheless, as the demands of World War I escalated, Austria-Hungary faced a shortage of handguns, leading to an increase in the production of the M1912. Moreover, countries such as Chile and Romania also expressed interest and placed orders for this pistol. Subsequently, when Germany annexed Austria in 1938, a new chapter unfolded for the M1912. The Wehrmacht placed an order for 60,000 M1912 pistols, which were rechambered to 9mm Parabellum, serving in the German military throughout World War II.

The Steyr M1912's design features a short recoil system, where the barrel unlocks from the slide through rotation. During firing, a lug and groove mechanism rotates the barrel 20° until a lug strikes a stop wedge, holding the barrel steady while the slide moves backward. The spent casing is then extracted and ejected through the action of the extractor claw against the breech face of the slide. As the slide returns forward under the force of the recoil spring, a new round is chambered from the magazine, and the locking system re-engages the barrel.

The pistol includes a safety lever on the left side of the frame, allowing it to be engaged and disengaged by turning it into a notch on the slide. Additionally, a disconnector system ensures that the pistol does not fire until the action is fully closed. The integral magazine, housed in the grip, allows the pistol to be loaded from above using eight-round stripper clips