Stable Ti(3+) self-doped TiO(2) with tunable phase composition and highly efficient visible-light photoactivity (ca. 32.7 times stronger than an undoped sample for ˙OH formation) was synthesized via a facile metallic zinc-assisted method. The surface Ti(3+) species can be stabilized by Zn doping, and the photocatalytic selectivity can be regulated by the phase composition.