The development of p-type metal-oxide semiconductors (MOSs) is of increasing interest for applications in next-generation optoelectronic devices, display backplane, and lowpower-consumption complementary MOS circuits. Here, we report the high performance of solution-processed, p-channel copper-tinsulfide-gallium oxide (CTSGO) thin-film transistors (TFTs) using UV/O 3 exposure. Hall effect measurement confirmed the p-type conduction of CTSGO with Hall mobility of 6.02 ± 0.50 cm 2 V −1 s −1 . The p-channel CTSGO TFT using UV/O 3 treatment exhibited the field-effect mobility (μ FE ) of 1.75 ± 0.15 cm 2 V −1 s −1 and an on/off current ratio (I ON /I OFF ) of ∼10 4 at a low operating voltage of −5 V. The significant enhancement in the device performance is due to the good p-type CTSGO material, smooth surface morphology, and fewer interfacial traps between the semiconductor and the Al 2 O 3 gate insulator. Therefore, the p-channel CTSGO TFT can be applied for CMOS MOS TFT circuits for next-generation display.