The 15 cm schwere Feldhaubitze M. 15 was a heavy howitzer used by Austria-Hungary in World War I. Austrian and Czech guns were taken into Wehrmacht service after the Anschluss and the occupation of Czechoslovakia as the 15 cm schwere Feldhaubitze 15(t) or (ö).

The M. 15 was adapted from a fortress turret howitzer called the 15 cm Turmhaubitze M15 designed to throw the same ammunition as the schwere Feldhaubitze M.14 some 3.5 kilometres (3,800 yd) further.

A total of 57 barrels and 56 carriages were completed by the end of the war.

[1] The Finns purchased twenty weapons after the end of the Winter War.

Some went to equip the Maaselkä Fortification Artillery Battalions.