Gun laying is the process of aiming an artillery piece, such as a gun, howitzer or mortar on land or at sea against surface or air targets. It may be laying for direct fire, where the gun is aimed similarly to a rifle, or indirect fire, where firing data is calculated and applied to the sights. The term includes automated aiming using, for example, radar-derived target data and computer-controlled guns.

Gun laying means moving the axis of the bore of the barrel in two planes, horizontal and vertical. A gun is traversed—rotated in a horizontal plane—to align it with the target; and elevated—moved in the vertical plane—to range it to the target.

Gun laying is a set of actions to align the axis of a gun barrel so that it points in the required direction. This alignment is in the horizontal and vertical planes. Gun laying may be for direct fire, where the layer sees the target, or indirect fire, where the target may be invisible from the gun. Gun laying has sometimes been called "training the gun".