This research seeks to identify factors that influence the self-determined behavior of nine adults with Down syndrome. A descriptive and ex post facto study is presented through the application of the INICO-FEAPS Scale on Quality of Life in a semi-structured interview format. Quantitative and qualitative analyzes have been carried out, adopting a mixed model. Quantitative analyses showed significantly lower levels in the self-determination and rights domains. Qualitative analyses revealed the existence of contextual barriers derived from overprotection, together with individual, natural and professional support as facilitators of self-determination. These results underline the importance of achieving an adequate balance between the types and intensities of supports, to guarantee the desired personal results without reducing self-determination.