A wafer processing method includes a protective film providing step of providing a protective film on the front side of a wafer, a wafer unit forming step of applying a liquid resin curable by an external stimulus to the front side of the wafer and then curing the liquid resin by applying the external stimulus to form a protective member, thereby forming a wafer unit composed of the wafer, the protective film, and the protective member in the condition where the front side of the wafer is covered with the protective member, a grinding step of holding the protective member on a holding surface of a chuck table and then grinding the back side of the wafer of the wafer unit to thereby reduce the thickness of the wafer, and a peeling step of peeling the protective member and the protective film from the wafer reduced in thickness.