We report the fabrication of amorphous (In x Ga 1-x ) 2 O 3 metal-semiconductor-metal ultraviolet (UV) photodetectors on glass substrate by co-sputtering. It was found that, we could change the cutoff wavelength of the fabricated photodetectors by changing the RF sputtering power of the In 2 O 3 target. With 5 V applied bias, it was found that the measured dark currents were 2 × 10 -12 , 1 × 10 -11 , and 2.3 × 10 -11 A for sample A prepared with 40 W In 2 O 3 sputtering power, sample B prepared with 50 W In 2 O 3 sputtering power, and sample C prepared with 60 W In 2 O 3 sputtering power, respectively. It was also found that the UV-to-visible rejection ratios were 3 × 10 3 , 5 × 10 3 , and 1.5 × 10 4 for samples A, B, and C, respectively. Furthermore, it was found that the response speeds of the fabricated devices were good.