In this paper, Gallium Nitride (GaN) Metal-Insulator-Semiconductor (MIS)-HEMTs are compared with conventional Schottky Metal-Semiconductor HEMTs in terms of DC and ESD performance. Measurement results indicate TLP failures are highly related to 2DEG channel driving capability. The impacts of different gate interfaces in the GaN (MIS)-HEMTs on failure mechanisms are the key factor of final ESD robustness.