A wafer processing system includes a laser processing apparatus, a grinding apparatus, a tape sticking apparatus, a first cassette placement part, a second cassette placement part, a conveying unit that conveys a wafer, and a controller that controls the respective constituent elements. The controller includes a first processing program instructing section that conveys a wafer unloaded from a first cassette in order of the laser processing apparatus, the grinding apparatus, the tape sticking apparatus, and a second cassette and sequentially carries out processing by each apparatus for the one wafer, and a second processing program instructing section that conveys the wafer unloaded from the first cassette in order of the grinding apparatus, the laser processing apparatus, the tape sticking apparatus, and the second cassette and sequentially carries out processing by each apparatus for the one wafer.