An ESD protection circuit for a differential I/O pair is provided. The circuit includes an ESD detection circuit, a discharge device, and four diodes. The first diode is coupled between the first I/O pin and the discharge device in a forward direction toward the discharge device. The second diode is coupled between the second I/O pin and the discharge device in a forward direction toward the second I/O pin. The third diode is coupled between the discharge device and the positive power line in a forward direction toward the positive power line. The fourth diode is coupled between the discharge device and the negative power line in a forward direction toward the discharge device. Via an output end, the ESD detection circuit triggers the discharge device during ESD events.