Quality of life is important for the development and evaluation of interventions for autistic people. It is a multidimensional concept, anchored in a sociocultural context and based on a person’s subjective assessment of their life. The aim of this study is to examine whether the determinants of perceived quality of life vary by country (or culture) by comparing two groups of French-speaking autistic adults ( n = 430), one in France and the other in Québec (Canada). A cross-sectional survey was conducted to provide information on the quality of life (Autism Quality of Life Measure—ASQoL), diagnosis and health conditions, self-evaluation of autistic traits (Autism-Spectrum Quotient—AQ10), and sociodemographic characteristics of these two samples. The results of our comparison of French-speaking autistic adults in France and Québec suggest that sociocultural context has an impact on autistic people’s quality of life ( r2 = 0.280). The Québec group reported a superior quality of life. The social experience of autism-related stigmatization emerges as a strong predictor of lower quality of life in both groups. However, the two groups differ with other predictors. This study demonstrates the importance of considering sociocultural context in measuring quality of life in autistic adults. It emphasizes the need for awareness programs and public campaigns aimed at identifying and countering stigmatization processes. Lay abstract What is already known about the topic? Quality of life refers to how people perceive aspects of their life such as physical health, material security, and interpersonal relationships. Studies have reported lower quality of life among autistic individuals than in the general population. What does this article contribute? This article contributes to a better understanding of quality of life and its measures from the point of view of autistic adults. By comparing two groups of French-speaking autistic adults from two different places (France and Québec—Canada), this research shows that the perception of quality of life and its determining factors differ for autistic adults living in each country. The Québec group reported a superior quality of life, and some quality of life predictors were different in each group. The social experience of autism-related stigmatization, however, was a powerful predictor of quality of life for all. Implications for practice, research, and policy To promote a higher quality of life for autistic people, it is important to consider the sociocultural context and implement awareness programs and public campaigns aimed at identifying and countering stigmatization processes.