This study aimed to identify the characteristics of social interactions in a child with autism spectrum disorder (ASD) across a regular classroom and small-group settings. We observed the interactions between the target child and peers in both settings. The episodic recording method was used for data collection, resulting in 11 episodes: five from the regular classroom and six from the small-group setting. The results revealed that: 1) the target child’s interaction patterns differed between the regular classroom and small-group settings; 2) the child became overly focused on winning in competitive situations, potentially overlooking others’ feelings; and 3) practice and increased confidence led to more positive interactions and verbalizations. These findings suggest the importance of considering multiple environments when assessing and supporting children with ASD as well as the potential benefits of structured practice in improving social interactions.