This paper presents the robust optimization of a galloping-based piezoelectric wind energy harvester (GPWEH) using Taguchi method. A mathematical model of the GPWEH is established for calculating the voltage output of the harvester. The Taguchi design method is used to formulate the experimental designs for the harvester with the parameters variations. The signal-to-noise ratio (S/N) of the voltage output is derived from the larger-the-better characteristic value of each experimental condition. The maximum S/N obtained from the effect analysis of the S/N of the voltage output is used to determine the optimal factorial combination of the parameter level. The results show that with the optimal design combination, the average voltage output of the harvester is 114.9 V at an excitation wind speed of 6 m/s, which is 12.4% higher than that from the original design combination. The study provides a guideline for the robust optimization of the GPWEH based on the Taguchi method.