Siblings of children who have been diagnosed with autism can play important roles in the lives of their brothers or sisters. Previous literature shows that siblings can effectively change behavior and can increase play interactions. Furthermore, the use of preferred materials may enhance social interactions between the siblings. The purpose of this study was to determine, the effects that material preferences and choices have on sibling social bids and cooperative play during a sibling training program. There were two main objectives. The first objective was to evaluate the effects of teaching with the high preference toy of the neuro-typical sibling during sibling training. The second objective was to determine if the training would produce different effects across four different toy conditions. Measures included social bids made by each of the siblings and cooperative play. Results indicate that teaching with the neuro-typical siblings' high preference toy during sibling training can be an effective method to increase social bids and cooperative play. The results of this study are discussed in the contexts of preference and choice selections, physical environments, motor skills, carry over effects, and participations based on gender.