In this work, the effects of surface orientation of the silicon (Si) substrates on the structural and morphological properties of zinc oxide (ZnO) thin films grown by radio frequency sputtering system were investigated. Silicon substrates with different surface orientations, i.e., Si(100), Si(111), and Si(110) were used. The structural properties of the ZnO thin films were investigated by X-ray diffraction (XRD) technique. The morphological properties of the deposited films were examined by field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). The XRD results reveal that all the deposited ZnO thin films exhibit a single phase wurtzite ZnO structure with preferred orientation along (002) direction. The FESEM images indicate a change from leave-like to granular-like structure for Si(100), (110) and (111) substrates, respectively. The AFM root mean square surface roughness for ZnO thin films on Si(100), (110) and (111) reveals a decreasing trend. From the results, it was suggested that the ZnO thin films grown on the Si(111) substrate has the best structural and morphological properties.