External control of the conductivity of correlated oxides is one of the most promising schemes for realizing energy-efcient electronic devices. Vanadium dioxide (VO2), an archetypal correlated oxide compound, undergoes a temperature-driven metalinsulator transition near room temperature with a concomitant change in crystal symmetry. Here, we show that the metalinsulator transition temperature of thin VO2(001) lms can be changed continuously from 285 to 345 K by varying the thickness of the RuO2 buffer layer (resulting in different epitaxial strains). Using strain-, polarizationand temperature-dependent X-ray absorption spectroscopy, in combination with X-ray diffraction and electronic transport measurements, we demonstrate that the transition temperature and the structural distortion across the transition depend on the orbital occupancy in the metallic state. Our ndings open up the possibility of controlling the conductivity in atomically thin VO2 layers by manipulating the orbital occupancy by, for example, heterostructural engineering. PUBLICATION ABSTRACT