ZnO based Diluted magnetic semiconductors (DMSs) have attracted broad interest for their promise functionalities in spintronics based devices. In this book, we explored the effect of different synthesis techniques (solid-state, sol-gel and chemical vapor deposition (CVD) methods) and synthesis parameters (sintering temperature, doping concentration, annealing atmosphere) on the structural and magnetic properties of TM (Mn, Co) doped ZnO. The effect of Al/Sb codoping on the magnetic properties of ZnMnO and ZnCoO were studied. We also explored the structural, optical and magnetic properties of nanowires and nanorods of Mn doped ZnO for their potential in spintronics based devices. From the experimental results presented in this book, it is concluded that defects like oxygen vacancies, zinc vacancies etc. in the samples are important for room temperature ferromagnetism in ZnO based DMSs.