An ESD protection circuit including a clamping module and a detecting module is provided. The clamping module is coupled between a positive power line and a negative power line. The detecting module includes a triggering unit, a resistor, and a MOS capacitor. An output terminal of the triggering unit is used for triggering the clamping module. The resistor is coupled between the positive power line and an input terminal of the triggering unit. The MOS capacitor has a first end and a second end. The first end is coupled to the input terminal of the triggering unit. During a normal power operation, a switching terminal of the triggering unit enables the second end of the MOS capacitor to be coupled with the positive power line. Thereby, the gate tunneling leakage is eliminated and the problem of mistriggering is prevented.