LaTiOx films have been grown on (001) perovskite oxide substrates by pulsed-laser deposition. Both single-phase perovskite LaTiO3 and layered La2Ti2O7 films could be stabilized by varying the oxygen partial pressure and substrate temperature during growth. We have obtained a crystallographic and electronic phase diagram for LaTiOx films, demonstrating the ability to vary the titanium valence from 3+ to 4+ in thermodynamically unfavorable growth conditions by utilizing interface energies.