In this study, the solid particle erosion behavior of solutionized, artificially aged (T6) and annealed aluminum alloy AA7075 has been investigated. The samples were eroded in solid particle erosion test equipment at 45 impingement angle and 75 m/s impingement velocity with 180 mesh garnet erodent particles. Afterwards, microstructures of solutionized, artificially aged and annealed samples of AA7075 alloy were analyzed. In order to figure out the effect of ductility on erosion rates, the Brinell hardness of the samples was measured. The surface morphology images of the samples were taken before and after the erosion test by using scanning electron microscope (SEM). The effects of the microstructures and the hardness on the erosion behavior of the different heat treated specimens were examined. Finally, SEM images of the samples were deeply analyzed and the erosion mechanisms which occurred on the surfaces of the samples were discussed.