A siege tower is a specialized siege engine, constructed to protect assailants and ladders whilst approaching the defensive walls of a fortification. The tower was often rectangular with four wheels and a height roughly equal to that of the wall or sometimes higher to allow archers to stand on top of the tower and fire into the fortification.

Used throughout antiquity in both the Far East and Europe, siege towers were of unwieldy dimensions and therefore mostly constructed on site of the siege. Taking a lot of time to construct, siege towers were mainly constructed if the defense of the opposing fortification could not be overcome by ladder assault, by sapping or by breaking walls or gates.