A shut off valve arrangement for use in a fuel injection system includes a shut off valve member (102; 202; 404; 500; 600) operable between a closed position in which the shut off valve member (102; 202; 404; 500; 600) is engaged with a shut off valve seating (118; 221; 512; 614) and an open position in which the shut off valve member (102; 202; 404; 500; 600) is disengaged from the shut off valve seating (118; 221; 512; 614) to control the supply of fuel to the injector through a fuel supply passage (8). The shut off valve member (102; 202; 404; 500; 600) includes a first surface that is exposed to fuel pressure within a shut off valve control chamber (70; 210; 414; 503), a second surface exposed to fuel within the fuel supply passage (8) and a third surface exposed to fuel pressure in a balance chamber (127; 224; 428; 532), wherein the shut off valve arrangement is provided with a control valve (44) for controlling the pressure of fuel within the shut off control chamber (70; 210; 414; 503), thereby to control movement of the shut off valve member (102; 202; 404; 500; 600) between the open and closed positions. The shut off valve arrangement is further provided with communication means between the fuel supply passage (8) and the balance chamber (127; 224; 428; 532) so that a balancing force acting on the third surface due to fuel pressure in the balance chamber (127; 224; 428; 532) opposes an opening force acting on the second surface.