Chemical disorder on the surface and lattice strain in GaN implanted by Fe10+ ions are investigated. In this study, 3-MeV Fe10+ ions fluence ranges from 1 × 1013 ions/cm2 to 5 × 1015 ions/cm2 at room temperature. X-ray photoelectron spectroscopy, high-resolution x-ray diffraction, and high-resolution transmission electron microscopy were used to characterize lattice disorder. The transition of Ga-N bonds to oxynitride bonding is caused by ion sputtering. The change of tensile strain out-of-plane with fluence was measured. Lattice disorder due to the formation of stacking faults prefers to occur on the basal plane.