An oxide thin-film transistor (TFT) is the foundational device of oxide electronics. Thus, acquiring a deep understanding of the device physics operation of an oxide TFT is a worthwhile endeavor. To this end, basic static and dynamic oxide TFT models are derived within the framework of appropriate equivalent circuits. The static model is then extended to account for more complicated, nonideal phenomena often encountered in the electrical assessment of a real oxide TFT. Finally, oxide TFT modeling via technology computer-aided design simulation is discussed.