Electroless Au plating (ELGP) on Pd thin films is performed. The ELGP time dependence on the surface morphology is investigated by a scanning electron microscope. Continuous nucleation and growth of hemispherical Au islands are observed as the plating time increases. Heteroepitaxial growth of the electroless plated Au on the Pd surface is confirmed by cross-sectional scanning transmission electron microscope images. Cross-sectional energy-dispersive X-ray spectroscopy reveals interdiffusion between the Pd atoms and the plated Au atoms at room temperature, which allows the formation of Au–Pd alloys. The heteroepitaxial Au growth on Pd is significant for reducing contact resistance of Au/Pd structures.