Periodic (CASTEP and DMol(3)) and cluster (Gaussian 98 and DMol(3)) ab initio calculations were carried out to develop force field parameters for the system Ti-O-H to model TiO2-H2O interfaces. A force field was derived from previously existing force fields for bulk TiO2 polymorphs (Matsui, M.; Akaogi, M. Mol. Simul. 1991, 6, 239) and water (SPC/E; Berendsen, H. J. C.; Grigera, J. R.; Straatsma, T. P. J. Phys. Chem. 1987, 91, 6269) that describes Ti in a variety of coordination environments, Ti-O-H bonding, and H-bonding on TiO2 surfaces. The force field was tested for its ability to reproduce ab initio structures of the hydrated (110) surface of alpha-TiO2 (rutile).