Self-determination, as a person dispositional characteristic, is indeed influenced by situational characteristics that shape actions across contexts. Research has also reported differences in self-determination as a function of personal factors, but there is a need to integrate this knowledge in a general model aiming to analyse the impact of contextual variables in adolescents with and without disabilities. An integrative model of self-determination and related contextual factors was tested through a structural equation modelling approach. Participants were adolescents that reported their perceptions on self-determination dimensions and opportunities. Results indicated that educational and family contexts impacted self-determination and provided further understanding on self-determination dimensions' entity and function. Relevant implications for self-determination measure, comprehension and promotion derived from this study are discussed.