Researchers have identified effective instructional strategies for teaching peer imitation, including embedded classroom-based interventions. However, there is a dearth of strategies that have been effective for teaching generalization of imitation skills to novel contexts. Building on previous research, we examined the use of progressive time delay to increase peer imitation in the context of a play activity for four preschoolers with disabilities. We conducted preference and reinforcer assessments to identify effective reinforcers for each child prior to intervention. We conducted a multiple baseline across participants design meeting contemporary single case standards and used visual analysis to identify a functional relation: the intervention package was associated with an increase in the participants' peer imitation in training contexts. The intervention also led to levels of peer imitation comparable to those of typically developing peers, as measured by a normative peer sample, and generalization to novel contexts.