Reading strategy interventions relying upon peer tutoring are a common way to foster poor readers' comprehension skills. Those interventions are based on the assumption that tutees benefit from the (higher) reading skills of their tutors. However, this interpersonal effect has not yet been tested explicitly because the effectiveness of peer tutoring is commonly analyzed separately for tutees and tutors or with aggregated data. The present study illustrates how interpersonal and individual effects of a peer-tutored reading strategy intervention can be estimated using dyads as units of analysis in structural equation modeling. To demonstrate the application of the model, data from an experimental intervention study comparing the effects of a peer-tutored reading strategy training and a control condition in Grade 4 (N = 68 dyads) were analyzed.