Some of the weapons saw limited service in the early years of the Iraqi insurgency, making them one of the more popular submachine guns being deployed by the U.S. military personnel in recent conflicts around the world.

The UMP was previously available in multiple calibres, however with a decline in global use of .40 S&W and .45 ACP, only the 9mm Parabellum variant is in production.

[2] The UMP was designed in the 1990s by Heckler & Koch (HK), as a cheaper, lighter alternative to the MP5,[5] which made heavy use of polymers.

[12] The UMP was originally designed for larger cartridges such as the .40 S&W and .45 ACP, to provide more stopping power against unarmoured targets, with slightly lower effectiveness at longer ranges.

A larger cartridge produces more recoil and makes it harder to control in fully automatic fire.

[11][13] The UMP is available in four trigger group configurations, featuring different combinations of semi-automatic, 2-round burst, fully automatic, and safe settings.

When the last round of the UMP is fired, the bolt locks open, and can be released via a catch on the left side.