ZnO nanostructures with Ga doping prepared by metal–organic chemical vapor deposition developed an interesting nanopagoda shape with exposed {111}, {112}, {201}, and {101} lateral planes instead of {100} and {110} in the usually observed ZnO nanorods or nanowires. The types of exposed planes strongly affect those properties relating to surface reactivity. In this work, we report the opto-electrical properties and chemical reactivity of the Ga-doped ZnO nanopagodas and ZnO nanowires. Ultraviolet responses of photodetectors demonstrated that Ga-doped ZnO nanopagodas not only possessed a faster electron–hole generation and recombination rate but also exhibited higher photocatalytic activities than the ZnO nanowires. The improved performance of Ga-doped ZnO nanopagodas is due to the enhanced O₂ and H₂O chemisorption reactivity of the {111}, {112}, {201}, and {101} planes relative to the {100} and {110} planes.