The P9 is a pistol developed by the German manufacturer Heckler & Koch. Development took place since the early 1960’s and production ran from 1969 to 1978. Development of the P9 started as the designers of the G3 wanted to develop a pistol based on the successful roller locked delayed blowback mechanism.

The P9S is mostly a steel pistol with some polymer elements on the frame. The P9 was the first pistol to feature the delayed roller locking mechanism, which was derived from the G3 battle rifle. The hammer is concealed within the slide. The P9S can be switched between single action and double action. The fixed barrel features polygonal rifling and allows for easy installation of silencers.

The P9 is a semi-automatic pistol. It fires the 9x19mm round from a 9 round magazine or the .45 ACP from a 7 round magazine. The effective range is a few dozen meters.

The P9 has been sold worldwide as a civilian, law enforcement an military pistol. The production of the original P9 started in 1969 and stopped in 1973 with only 510 produced. The design was updated with a double action trigger and produced under the name P9S. Currently the P9 remains in limited use and has often been replaced by newer pistols.