A semiconductor structure for electrostatic discharge (ESD) protection is provided. The semiconductor structure includes a substrate, a first doped well, a source doped region, a drain doped region, and a gate structure. The first doped well is disposed in the substrate and has a first conductive type. The source doped region is disposed in the substrate and has a second conductive type opposite to the first conductive type. The drain doped region is disposed in the substrate and has the second conductive type. The gate structure is disposed on the substrate and between the source doped region and the drain doped region. The gate structure is separated from the source doped region.