A multiple baseline design was employed to evaluate the effectiveness of a sibling training package including modeling, role-play, and feedback on play and engagement between children with autism and their siblings. The results of two experiments suggest that, following training, siblings of children with autism correctly implemented all trained interaction components. Additionally, Experiment II assessed and programmed generalization to other materials and a non-training setting. The results showed that some unprogrammed generalization to non-trained toys occurred. Conversely, siblings engaged in trained skills in a non-training setting (home) only following the experimenter's instructions to generalize. In both experiments, the siblings' overall engagement and physical proximity of play in training sessions increased significantly above baseline. This study extends previous research in that it includes additional stimulus and response generalization measures.