(-201) oriented β-Ga<sub>2</sub>O<sub>3</sub> has the potential to be used as a transparent and conductive substrate for GaN-growth. The key advantages of Ga<sub>2</sub>O<sub>3</sub> are its small lattice mismatches (4.7%), appropriate structural, thermal and electrical properties and a competitive price compared to other substrates. Optical characterization show that GaN layers grown on (-201) oriented β-Ga<sub>2</sub>O<sub>3</sub> are dominated by intense bandedge emission with a high luminescence efficiency. Atomic force microscopy studies show a modest threading dislocation density of ~10<sup>8</sup> cm<sup>-2</sup>, while complementary Raman spectroscopy indicates that the GaN epilayer is of high quality with slight compressive strain. Room temperature time-findings suggest that the limitation of the photoluminescence lifetime (~500 ps) is due to nonradiative recombination arising from threading dislocation. Therefore, by optimizing the growth conditions, high quality material with significant optical efficiency can be obtained.