An electro static discharge (ESD) protection circuit including a signal transmission line coupled to an external input terminal, the ESD protection circuit including: a first power line coupled to a high voltage power supply; a second power line coupled to a low voltage power supply; a plurality of first oxide thin film transistors coupled in parallel between the first power line and the signal transmission line, the first oxide thin film transistors being diode-connected; and a plurality of second oxide thin film transistors coupled in parallel between the signal transmission line and the second power line, the second oxide thin film transistors being diode-connected.