The 9.15 cm leichtes Minenwerfer System Lanz (Trench mortar) was a light mortar used by Germany and Austria-Hungary in World War I, developed from the 9cm glatter leichter MinenWerfer Mauser by Firma Heinrich Lanz & Co.

The tube was made thicker and stronger which allowed for more powerful powder to be used, the breech was beefed up, and the safety pin closing system replaced with a screw locking system.

The platform was made stronger and had more room for accessories than the Mauser.

It was chosen by the Austrians as an interim replacement for their 9 cm Minenwerfer M 14, pending development of a superior domestic design, which eventually turned out to be the 9 cm Minenwerfer M 17.

The older Austrian design had a prominent firing signature, a less effective bomb and shorter range than the Lanz.