A lithographic apparatus having an illumination system configured to provide a radiation beam; a support structure configured to support a patterning device, the patterning device being capable of imparting the radiation beam with a pattern in its cross-section, thus providing a patterned radiation beam; a substrate table configured to hold a substrate; a projection system arranged to project the patterned radiation beam onto a target portion of the substrate, and a projection system support configured to support the projection system on a reference frame. The lithographic apparatus further includes a thermal conditioning system configured to thermally condition the projection system support. The invention further relates to a thermal conditioning system constructed and arranged to thermally condition a projection system support. The invention further relates to a device manufacturing method and a method for manufacturing a device.