Preschool teachers from a high-poverty, urban school district were trained to implement Story Talk, a book reading intervention designed to increase children's vocabulary and language development using supportive materials and strategic individualized coaching. Thirty-five teachers were randomly assigned by site to the intervention (20) or the control condition (15). Teachers in the intervention were provided with training; one-to-one, bi-monthly coaching; and Story Maps that included target vocabulary, open-ended questions to promote conversations during book reading, and suggested extension activities that support use of target vocabulary. The results suggested that teachers in the intervention increased on the global quality of their instruction, as well as on their fidelity to the project's strategies and their use of target vocabulary words. In addition, children in the intervention classrooms performed significantly better on measures of taught vocabulary words, and HLM analyses found gains on the Peabody Picture Vocabulary Test-4 (d?=?0.19) and the Expressive One Word Picture Vocabulary Test-4 (d?=?0.14), both standardized measures of vocabulary development. The results suggest that Story Talk holds promise as a relatively resource-conservative PD intervention that can be implemented with fidelity and can significantly improve children's vocabulary development, especially among children in high-poverty schools.