This study examined whether a storytelling and story-acting practice (STSA), integrated as a regular component of the preschool curriculum, can help promote three key dimensions of young children's school readiness: narrative and other oral-language skills, emergent literacy, and social competence. A total of 149 low-income preschoolers (almost all 3- and 4-year-olds) participated, attending six experimental and seven control classrooms. The STSA was introduced in the experimental classrooms for the entire school year, and all children in both conditions were pre- and post-tested on 11 measures of narrative, vocabulary, emergent literacy, pretend abilities, peer play cooperation, and self-regulation. Participation in the STSA was associated with improvements in narrative comprehension, print and word awareness, pretend abilities, self-regulation, and reduced play disruption. For almost all these measures, positive results were further strengthened by the frequency of participation in storytelling by individual children, indicated by number of stories told (NOST). The STSA is a structured preschool practice that exemplifies child-centered, play-based, and constructivist approaches in early childhood education, and that can operate as a curriculum module in conjunction with a variety of different preschool curricula. This study confirmed that it can contribute to promoting learning, development, and school readiness for low-income and otherwise disadvantaged children.