Why is this an important issue? In this study, we looked at how autistic traits might affect self-determination and quality of life. Quality of life is the way that you feel about your own life circumstances. In this study, we looked at four aspects of quality of life­psychological (e.g., mental health), social (how you interact with other people), physical (e.g., disability or sickness), and environmental (e.g., where you live). Self-determination is the ability to choose based on your own wants, needs, and interests, without feeling pressured. To be self-determined, you need to meet your needs for autonomy (experiencing free choice), competence (feeling able to do things effectively), and relatedness (feeling connected with others). Meeting these needs is affected by the world around you (e.g., where you live, if you have a job, whether you are disabled) and by the actions and beliefs of the people around you. People with higher autistic traits report, on average, lower quality of life and self-determination than people with lower autistic traits. Because other researchers have found that self-determination influences quality of life, lower levels of self-determination might partly explain lower quality of life. Programs that promote self-determination may reduce the gap in quality of life between autistic and non-autistic people. What was the purpose of this study? We thought that self-determination might partly explain why people with higher autistic traits report lower quality of life than people with lower autistic traits, so we wanted to test this idea. What did the researchers do? We asked people to answer questions about autistic traits, self-determination, and quality of life in an online survey. We statistically analyzed their answers to find out whether autistic traits influenced the levels of self-determination (feelings of autonomy, competence, and relatedness) or quality of life (psychological, social, physical and environmental quality of life). What were the results of this study? Autistic traits did not directly influence psychological, physical, or environmental quality of life but did directly influence social quality of life. In our study, people with higher autistic traits reported less satisfaction of their psychological needs than people with lower autistic traits. People with lower satisfaction of psychological needs also reported lower quality of life. Autistic traits influenced self-determination, which in turn influenced quality of life. What do these findings add to what was already known? To the best of our knowledge, this was the first study to explore relationships between autistic traits, self-determination, and quality of life. Our results showed that people with higher levels of autistic traits may report lower quality of life partly because autistic traits might make it difficult to become self-determined. What are the potential weaknesses in the study? We investigated self-determination and quality of life among one group of people from the general population. We did not compare autistic and non-autistic people. While some studies have shown that people with high levels of autistic traits may be similar to autistic people in some ways, this is not necessarily the case all the time. We cannot assume that results will be the same in other groups, that autistic traits cause lower self-determination, or that lower self-determination causes lower quality of life. We also did not consider all the things that might have influenced self-determination or quality of life (e.g., where people lived, how much money they had, or what their health was like). How will these findings help autistic adults now or in the future? People with higher autistic traits (including autistic adults) may find it harder to be self-determined both because of their autistic traits (e.g., difficulty in social interaction, sensory sensitivities) and also because school, work, and community systems may not be designed to support acceptance of differences. The results from this study suggest that higher autistic traits might make it difficult to meet the psychological needs for autonomy, competence, and relatedness. Research that compares autistic and non-autistic people is needed to determine both personal and environmental factors which may support the development of self-determination in autistic people and empower them to achieve higher quality of life.