A lithographic apparatus including: a radiation system; a frame; a substrate table for holding a substrate; and a scanning mechanism. The radiation system is operable to produce a radiation beam. The substrate table is moveably mounted to the frame and arranged such that a target portion of the substrate is arranged to receive the radiation beam. The scanning mechanism is operable to move the substrate table relative to the frame so that different portions of the substrate may receive the radiation beam. A mechanism is operable to determine a quantity indicative of a velocity of the radiation system relative to the frame. An adjustment mechanism is operable to control a power or irradiance of the radiation beam so as to reduce a variation in a dose of radiation received by the substrate as a result of relative motion of the radiation system and the frame.