A sparkgap assembly for a surge voltage arrester is provided with a plurality of elongated electrodes mounted between stacked plates of insulating material to form a zigzag discharge path through the sparkgap assembly when it is sparked over. The sparkgap assembly is provided with uniquely formed end plates that provide corona shielding and contact the outer electrodes of the assembly in a manner such that these electrodes develop an arc-moving, horngap effect when an overvoltage surge is discharged through the assembly.