Wind turbines play Important part in the worldwide transition to renewable energy, but, at the same time, their long-term operation and reliability are threatened by mechanical and environmental stresses. This dissertation presents a broad perspective on the approaches related to vibration-based damage assessment as predictive maintenance and safety tools for wind turbines. This work thoroughly deals with using different structural health monitoring techniques over a wide range of critical components of the wind turbine, like blades, gearboxes, towers, and foundations. The primary research on wind turbine blades focuses on vibration analysis techniques that monitor anomalies and progressive wear that could lead to blade failure.