Abstract We demonstrated selective self-oriented growth of triclinic tungsten trioxide (δ-WO3) films with (2 0 0), (0 0 2), and (0 2 0) orientations on polycrystalline AlN substrate using metal-organic chemical vapor deposition (MOCVD) by changing W(CO)6 vaporization temperature. At deposition temperatures of 1123–1223 K and total chamber pressure of 0.2 kPa, the orientation of δ-WO3 films changed from (2 0 0) to (0 0 2) to (0 2 0) to (0 0 2) plane as the increase of W(CO)6 precursor vaporization temperature from 333 to 353 to 373 to 393 K. The (2 0 0)-, (0 0 2)-, and (0 2 0)-oriented δ-WO3 films exhibited high deposition rates of 42, 213, and 317 μm h−1, respectively.