A method for manufacturing a linear lighting device, the method comprising the steps of providing a sheet of optically transmissive material, a sheet of thermally conductive material, and a plurality of light sources, arranging the light sources on the sheet of thermally conductive material, roll forming the sheet of thermally conductive material into a supporting heat spreader profile, roll forming the sheet of optically transmissive material into a first shape to cover the light sources and define an optical chamber, attaching end portions of the sheet of optically. The method enables the use of a lower amount of material and provides an efficient method for mass manufacturing linear lighting devices.