Laser shock processing (LSP) has been applied to polycrystalline -Al2O3 ceramics. X-ray characterizations have revealed that LSP results in significant compressive residual stresses which can extend to a depth of more than 1.2mm from the surface. The presence of compressive residual stresses improves the resistance of -Al2O3 ceramics to indentation cracking. Microstructural characterization suggests that the majority of -Al2O3 grains on the surface remains intact after LSP. However, damaged regions are occasionally present, which shows intergranular fractures and a limited plastic deformation in the vicinity of grain boundaries.