Background: Children with Prader-Willi Syndrome (PWS) display impaired pretend play abilities, reflective of broader social-cognitive challenges. Pretend play interventions for children with PWS demonstrate preliminary efficacy for improving cognitive and affective processes in play. It is unknown which specific intervention strategies, such as prompting, summarization, and modeling, most effectively improve these skills. The present study examined the effectiveness of different interventionist strategies on eliciting child behaviors within pretend play intervention sessions. Methods: Participants included 21 children (ages 6-12) with PWS who participated in a pretend play intervention. Recorded intervention sessions were coded for interventionist strategies and child pretend play skills. By pairing each interventionist strategy with the immediately following child behavior, it was possible to discern the frequency of how often certain intervention strategies immediately preceded various child pretend play skills. Results: All intervention strategies were followed by child pretend play over 50% of the time. Interventionist summarizing/reflection and modeling most often preceded child pretend play, as well as specific skills of imagination and organization. Prompting, followed by modeling, most often preceded affect expression. Conclusions: Interventionist strategies of summarization and modeling may most effectively facilitate pretend play. Prompts for emotions may be more effective to elicit affect expression, potentially due to social-cognitive difficulties inherent in PWS. Children with developmental differences may benefit from adults who engage in play as a partner, rather than direct the play, to help the child stay on-task and learn target behaviors. This insight may strengthen future efforts to support socioemotional skills through pretend play.