Real-time, proportional deployment of an Active Gurney Flap (AGF) located near the trailing edge of the wind turbine blade on the pressure surface is used to modulate aerodynamic performance. Wind tunnel experiments are conducted using an AGF model based on the geometry of a commonly used wind turbine blade over a range of Re numbers from 160 ,000 to 414 ,000, angle of attack (AOA) from - 1 0 ◦ to 1 5 ◦ , and AGF deployment positions from 0 ◦ to 1 3 5 ◦ . The torque required to raise and lower the AGF was measured and found to be approximately C T = 0 . 1 , independent of the deployment rate and the Re number. Aerodynamic force measurements demonstrate that the deployment of the AGF is capable of improving the lift and pitch moment performance with an increased lift-to-drag ratio. Aerodynamic changes are proportional to the AGF deployment angle, with a maximum effect observed at 7 0 ◦ to the chord. The aerodynamic changes occur instantly as the flap is deployed, although sudden changes in aerodynamic loading induce mechanical vibration of the wind tunnel model on the supporting sting.