Systems and methods for forming radius fillers for composite structures are disclosed herein. The systems include a sheet-locating structure that has a first support surface and a support surface edge. The systems further include a second support surface, a separation device, a conveyance structure, and a layup surface. The methods include locating a sheet of composite material on a first support surface and translating the sheet of composite material such that a first portion of the sheet is supported by the first support surface and a second portion of the sheet extends past the support surface edge. The methods also include supporting the second portion of the sheet with a second support surface and separating the second portion of the sheet from the first portion of the sheet to form a strip of composite material. The methods further include conveying the strip of composite material onto a layup surface.