Wind energy is regarded as a critical point within the global energy market, especially for those countries that depend on this source to produce electrical energy. The efficiency of wind energy is, to a large extent, dependent on the efficiency of the transmission system parts, such as the gear. In wind energy, the gear is involved in the transmission of mechanical energy from the rotor to the generator. The intention of this study is to assess and compare the performance of spur and chevron gears in wind turbines, to fill the gap regarding the difference between theoretical and experimental efficiency related to high-speed winds. The study was based on comparisons of the performance between the theoretical and experimental results, and the results reveal that the difference between the theoretical and experimental performances for the spur gears was very low (less than 0.1%), indicating the accuracy of the theoretical models and their applicability to high-speed performance. Furthermore, the results indicated a significant discrepancy (up to 0.46%) for the chevron gears, related to certain elements not considered in the theory, such as lateral friction. In conclusion, this study demonstrated that spur gears are more reliable in predicting efficiency while calling for the development of more comprehensive theoretical models for chevron gears.