A method for installing tower fittings by introducing at least two separate supply modules into a wind turbine tower, wherein a separate supply module structurally includes one segment each of at least two system components of the wind turbine tower, and wherein an upper segment end is arranged on an upper edge, and a lower segment end on a lower edge, of the supply module, including: arranging the upper edge of a first separate supply module at an upper end of the wind turbine tower; connecting an upper segment end of the first separate supply module to a lower segment end of a corresponding system component of a second separate supply module; and arranging the upper edge of the second separate supply module at the upper end of the wind turbine tower.