The Steyr M is a series of semi-automatic pistols developed by Steyr Mannlicher GmbH & Co KG of Austria for police services and the civilian shooting market. Design work on the new pistol began in the early 1990s and the final product known as the M9 was officially unveiled in the spring of 1999. The M40 version chambered in .40 S&W was developed before the M9, followed later by the M357 and two smaller variants of the M9 and M40 designated the S9 and S40 respectively. These pistols were developed primarily for concealed carry and have a shortened barrel, slide, smaller frame and a reduced magazine capacity. In 2013, the Steyr M (Medium) and S (Small) form factors were complemented by the L (Large) sized series and the C (Compact) sized series both available in 9×19mm Parabellum and .40 S&W chamberings as the L9-A1, L40-A1, C9-A1 and C40-A1.

Steyr Arms is a firearms manufacturer based in Sankt Peter in der Au, Austria. Originally part of Steyr-Daimler-Puch, it became independent when the conglomerate was broken up in 1989. Prior to 1 January 2019, the company was named Steyr Mannlicher AG. In April 2024, the company was acquired by Czech holding RSBC, which owns also Slovenian gun maker Arex Arms.