Sc-doped ZnO thin films were deposited on Corning 1737 glasses by using RF magnetron co-sputtering system with Sc2O3 and ZnO targets. Different sputtering powers of Sc2O3 target and post annealing of 550°C for 2 hr were investigated to understand the effect on microstructural, optical and electrical properties of Sc-doped ZnO thin films. From X-ray diffraction (XRD) results, the Sc-doped films have (002) preferred orientation. Cross-sectional scanning electron microscope (SEM) show that the Sc-doped ZnO thin films have columnar structure before and after annealing procedure. Atomic force microscopy (AFM) surface measurement also shows that the surface roughness of the films was smoother when the Sc2O3 sputtering power increased. The optical transmission of as deposited Sc-doped films in the visible region all exceeded 80%, and increased about 3% after samples annealed. Electrical resistivity measurement reveals that the as-deposited Sc-doped ZnO thin films had lowest resistivity of 0.97 Ω cm when the Sc2O3 sputtering power was 125W. After annealing the lowest resistivity decreased to 9.85 × 10−2 Ω cm in which 200W of the Sc2O3 sputtering power was applied.