Quasi-resonant flyback converter is realized with the aim to demonstrate the topology feasibility using the normally-on switching behaviour of the gallium nitride (GaN) power transistor. Reference converters utilize GaN and silicon-based MOSET as the switching devices to compare the electric characteristics, and power losses. Quasi-resonant technology offers reduced turn-on losses, resulting in increased efficiency and lower device temperature. The turn-on losses dominate the power losses as the switching frequency of the power supply increases. The combined advantages of gate charge and on-resistance for GaN in the 60 watt reference converter leads to improve the turn-off conduction loss. GaN based power converter provides up to 7.02% improved efficiency over silicon based MOSFETs. The converter performance improvement opens the possibility of fully exploiting the wide advantages of GaN transistors in power electronic application.