SnS nanosheets (NSs), SnS nanowires (NWs) and SnS2 nanosheets were synthesized and investigated as counter electrode (CE) catalysts in a I3−/I− based dye-sensitized solar cell (DSC) system for the first time. It is found that the SnS NS based DSCs show comparable power-conversion efficiency (Eff = 6.56%) to Pt (7.56%), while the Eff of SnS NW and SnS2 NS based DSCs are 5.00% and 5.14% respectively, indicating the excellent catalytic activity of SnSx for the reduction of triiodide to iodide.