Tb-doped SiO2 nanowires have been synthesized through a vapor−liquid−solid (VLS) mechanism. The morphology and compositional characteristics of the doped nanowires have been investigated by various microscopy techniques. The prepared nanowires have amorphous characteristics with a diameter distribution range from 15 to 30 nm and a length up to several micrometers. Photoluminescence properties of pure SiO2 nanowires and Tb-doped SiO2 nanowires have been investigated, respectively. It shows that pure SiO2 nanowires have a broad green emission band with a maximum around 515 nm, which is related to the hydrogen-related species (⋮Si−H and ⋮Si−OH). While Tb3+-doped SiO2 nanowires have novel green emissions both from the doped Tb3+ ions and the host SiO2 nanowires. The relationship between the two kinds of emissions has also been investigated. These Tb-doped amorphous SiO2 nanowires exhibit great potential to act as a novel green-emitting phosphor.