The radar micro-Doppler signatures of wind turbines have been discussed in this chapter. Due to the extremely large dimension and blade rotation, an increasingly large number of wind turbines have become potential interference to radar operations. The interactions between wind turbines and radar especially weather radars are analyzed, and some examples have been given to showcase the clutter characteristics. As a result of the blade rotation, wind turbines have unique micro-Doppler radar signatures that are best perceived in the time-frequency analysis. The Doppler flashes extend through the entire spectrum, making it difficult to mitigate in the Doppler domain. The scaled measurements of the wind turbine model have been implemented to better understand the complex micro-Doppler radar signatures and its dependency on wind turbine motions in a controlled laboratory environment. Both frequency and time domain measurement approaches have been used. Some interesting EM phenomenon and statistical variables are studied from the scaled measurement results. However, the scaling factor limits our ability to interpret the spectrum by compromising the relative Doppler spectrum resolution. Hence, a mobile radar has been deployed to better perceive the details of wind turbine micro-Doppler signatures. The wind turbine is a new form of radar interference that features extremely complicated micro-Doppler signatures. The radar return variations of wind turbines with respect to their position, shape, material, and radar parameters, etc. are still being studied and there are many aspects that are not covered in this chapter. More extensive studies from physical models, radar signature analysis to mitigation approaches are needed.