This exploratory study investigated how 2 years of a coaching-based language and literacy intervention were linked to Head Start teachers' classroom environments and instructional interactions, as well as to the vocabulary, alphabet, and sound awareness learning of their preschool students. In total, 16 Head Start teachers participated in the intervention, and 10 teachers participated in a business-as-usual control. In addition, 626 preschoolers participated in the intervention, while 357 children participated in the control condition. The first year of coaching was linked to gains in the quality of teachers' classroom literacy environments and the quality of instructional interactions, and a second year of coaching resulted in additional gains in the quality of instructional interactions. Effects were consistent regardless of the initial quality of the classroom environment and instructional interactions. The intervention was significantly related to all child outcomes, with greater vocabulary gains in the second year of coaching. (Contains 7 tables and 1 note.)