In contrast to typically developing children, children with autism rarely exhibit cooperative social behavior. To examine whether this problem reflects global developmental delays or autism-specific deficits, the present study compared cooperation, emotional understanding, personality characteristics, and social behavior of 10 children with autism who had average IQ to those of 16 children with Attention-Deficit/Hyperactivity Disorder (ADHD) and Oppositional Defiant Disorder (ODD) and 10 typically developing children. In cooperative behavior, level of emotional understanding, and aloof behavior, the autism group outperformed the ADHD/ODD group and did not differ significantly from typically developing children. However, the autism group showed worse emotion recognition and more active-but-odd behavior than the other groups. The results indicate that high-functioning children with autism can develop cooperative social behavior and advanced theory of mind abilities, but continue to show deficits in identifying emotions and displaying socially appropriate behavior.