GaAs high-electron-mobility transistors (HEMTs) have been widely used for radio-frequency (RF) applications due to the excellent material properties. One of the essential elements of the HEMTs is the gate Schottky barrier layer. InGaP has been proposed and proven as a better Schottky barrier material for the RF performance of the GaAs HEMTs. This letter investigates the influence of the GaAs HEMTs with two different Schottky layers, which are InGaP and AlGaAs on device transient characteristics under electrostatic discharge (ESD) stress. Although InGaP presents significant advantages on improving RF performance of GaAs HEMTs, it shows inferiority in ESD robustness.