This study investigated the effect of a large group narrative intervention on diverse preschoolers' narrative language skills with aims to explore questions of treatment efficacy and differential response to intervention. A quasi-experimental, pretest/posttest comparison group research design was employed with 71 preschool children. Classrooms were randomly assigned to treatment and comparison conditions. Intervention consisted of explicit teaching of narrative structure via repeated story retell practice, illustrations and icons, and peer mediation. Children's narrative language and comprehension were assessed at Pretest, Posttest, and 4 weeks after treatment. Statistically significant differences between treatment and comparison groups were found on retell and story comprehension measures. A priori classification criteria resulted in 28 percent of the participants identified as Minimal Responders on the story retell measure and 19 percent as Minimal Responders on the story comprehension measure. Children who were dual-language learners did not have a different pattern of response than monolingual English speakers. Low-intensity narrative intervention delivered to a large group of children was efficacious and can serve as a targeted language intervention for use within preschool classrooms. A culturally and linguistically appropriate, dynamic approach to assessment identified children for whom intensified intervention would be recommended. (author abstract)