Epitaxial SrTiO3(STO) thin films have been grown successfully on Si(001) buffered with single and double buffer layers by pulsed laser deposition. Depending on the buffer structure and under appropriate substrate temperature and oxygen pressure values, epitaxial films are grown with single orientations. Epitaxial STO films with (0hh), (00h), and (hhh) out-of-plane orientation have been obtained for the first time on yttria-stabilized zirconia (YSZ)ySi(001), CeO2/YSZ/Si(001), and TiN/YSZ/Si(001), respectively. Secondary ion mass spectrometry analyses show sharp interfaces and good uniformity of the elements in each layer. The films are practically free of droplets, and the rms value of roughness is smaller than 0.5 nm.