Nearly 50,000 people with autism spectrum disorders (ASD) will become adults this year alone, and the number of adults with ASD will increase rapidly in the coming years. Because of this, effectively addressing the substantial and varied needs of this growing population is one of the greatest challenges currently faced by both service providers and the autism research community. Unfortunately, adults with ASD often function very poorly in terms of employment, education, and the development of social relationships. We know very little about why this is the case. This lack of understanding greatly limits our ability to develop treatments that might help people with ASD thrive in adult life. Stress factors heavily into adult life, and its successful management is essential for healthy adjustment. Recent but limited research suggests that children with ASD may react very poorly to stress in social situations. We know that adults with ASD are likely to have a difficult time handling stress. We also know that their responses to stress are probably different from adults who do not have ASD. However, we do not know how adults with ASD react to stress and how they perceive stress. It is also possible that there is an important connection between the way that adults with ASD handle stress and their adjustment to life in adulthood. Without A clear understanding of how stress reactions affect outcomes in adult life for people with ASD is required for the development of treatments that aim to improve stress reactions in adulthood for this population. This study will examine stress reactions in adults with ASD. It will also make the connection between stress reactions and functioning in adulthood for people with ASD. This will help us to understand differing stress responses among a growing and diverse population of adults with ASD. This study has three key goals. First, this study will examine the differences in stress response between adults with ASD and adults who do not have ASD. Second, it will examine the relationship between stress and meaningful adult outcomes for people with ASD. Finally, it will use advanced statistical procedures to identify meaningful subgroups in terms of stress response for adults with ASD.