The first ambipolar oxide-based thin-film transistor (TFT) using an SnO channel is presented, demonstrating operation of a complementary-like inverter configured by two ambipolar SnO TFTs. Saturation mobilities of similar to 0.8 and similar to 5 x 10(-4) cm(2) V-1 s(-1) are obtained for the p-channel and n-channel modes, respectively, and the inverter shows a maximum voltage gain of similar to 2.5. This is the first demonstration of a complementary-like circuit using a single oxide semiconductor channel and provides an important step toward practical oxide electronics.