In this study, the impact of growth in turbine size on aerodynamic rotor performance of modern commercial large-scale wind turbines was investigated. For this examination, three different commercial large-scale wind turbines of models VESTAS V80-2MW, V90-3MW, and V126-3.3MW operating on three existing onshore wind farms were selected. In order to determine the effects of turbine size growth on aerodynamic rotor performance, turbine power output P, turbine power coefficient, C-p, turbine rotational speed, ohm, thrust force, T, tip speed ratio, lambda, and flow angle, phi, values obtained from these turbines were compared at the same magnitude of free-stream wind speeds, U-infinity. The results reveal that decreasing specific power decreases the rated output wind speed of the wind turbines; hence, the reduction in the rated output of wind speed contributes to the tendency of higher power capacity. Moreover, it was determined that the enlargement in the turbine size has a profound influence on the parameters that affect the performance of the turbine such as rotational speed, ohm, thrust force, T, tip-speed ratio, lambda, and flow angle, phi. For instance, higher thrust loads and tip-speed ratios were acquired for the turbines having a larger rotor diameter which results in better aerodynamic efficiency of the turbine.