A fuel injector for fuel-injection systems of internal combustion engines. The valve includes an electromagnetic actuating element having a solenoid coil, a fixed core, an outer magnetic-circuit component and a movable armature to actuate a valve-closure member which cooperates with a valve-seat surface provided on a valve-seat member. The valve is characterized by its extremely small outside dimensions. The entire axially movable valve needle, including armature and valve-closure member, has a mass of only m