Alumina is a common contaminate of titania, which is found in paints and food additives. Recently, thin films of rutile TiO2 grown on sapphire (α-Alumina) have received attention for possible use in electronic and optical devices.1−3 However, the alumina-titania interface has not been well characterized. In this work we report an extensive analysis of the alumina-titania interfacial relationship. Using existing structural data4, models of common alumina and titania surfaces have been constructed. The model used maximizes the commensurability between the two structures. Semi-empirical/tight binding calculations have been employed to examine the monolayer as well as the interfacial electronic properties in terms of chemical interaction potential and stability.