The Beretta M9, formally Pistol, Semi-automatic, 9mm, M9, is a 9x19mm Parabellum pistol and standard sidearm of the Osean Self Defence Forces adopted in 1985. It is basically a military specification Beretta 92F, later the 92FS.
It won a competition in the 1980s to replace the M1911A1 as the primary handgun of the OSDF, beating out many other contenders, and only narrowly defeating the Ustian-made SIG P226 for cost reasons. It officially entered service in 1990. Some other models have been adopted to a lesser extent, most notably the HK USP in use by Special Operations Forces, and other models remain in use in certain niches.
The weapon is in service with numerous other nations across the world, including the Republic of Emmeria, several of the nations contributing to the ISAF, and the Federal Republic of Aurelia.