Sputtered ZnO-SiO2 nanocomposite light-emitting diodes (LEDs) were treated using a flat-top nanosecond laser (FTNL) under room temperature. The intensity of the 376 nm electroluminescence (EL) emission of ZnO-SiO2 nanocomposite LEDs at a current of 9 mA with FTNL treatment was approximately 1.4 times greater than LEDs without FTNL treatment. Furthermore, the FTNL-treated LEDs indicated a narrower full width at half maximum of the 376 nm EL emission than those of LEDs without FTNL treatment. Thus, FTNL treatment of ZnO-SiO2 nanocomposite LEDs could induce the recrystallization of distributed ZnO nanoclusters and reduce the defects in ZnO-SiO2 nanocomposite layers.