In this paper, a robust H-infinity based controller is proposed and implemented for a doubly-fed induction generator (DFIG) based wind turbine to improve the system transient stability under fault conditions. The proposed controller is based on H-infinity techniques to minimize the H-infinity norm from inputs to outputs. In order to make a comprehensive analysis, the performance of the H-infinity controller is compared with that of conventional PI controller. Simulation results confirm the efficacy of the proposed controller in enhancing transient stability. The effect of external disturbance in enhancing the stability of the system is also demonstrated.