An electrostatic discharge (ESD) protection device includes a substrate including a plurality of active fins and a plurality of grooves. The ESD protection device includes an insulation layer on the active fins and the grooves, and a gate electrode on the active fins. The ESD protection device includes a first impurity region adjacent to a first side of the gate electrode, and a second impurity region adjacent to a second side of the gate electrode. The second side of the gate electrode may be arranged opposite to the first side. The ESD protection device includes an electrode pattern of a capacitor overlapping the first impurity region, a resistor overlapping the second impurity region, and a connection structure electrically connecting the electrode pattern, the gate electrode, and the resistor to each other.