This mixed methods research explored the autonomous experiences of South African school students when participating in a science fair. A prominent global goal for school science education is for students to partake in scientific inquiry in order to acquire understanding of science concepts, the processes and skills of science, and the nature of science. This places a demand on teachers as it requires a change in pedagogy from a teacher-centred to a student-centred approach. Student autonomy, has been described as both a rationale for and a characteristic of students doing scientific inquiry. In this research, a quantitative survey questionnaire was administered to 50 students participating in a science fair. The questionnaire sought to establish the autonomy level of students when doing their investigative inquiry projects and the degree of support they received. Thereafter, 5 students were interviewed to elaborate upon their responses and to describe in detail their experiences of doing the projects. The findings of this study revealed that the students enjoyed optimal autonomy and perceived their experience as being empowering and stimulating. It is also suggested that science fairs can provide an opportunity for students to enjoy autonomy in choosing their own topic for inquiry, in designing the inquiry, in doing the inquiry, and arriving at their own conclusions. This autonomy can enable students to experience authentic inquiry, show their creativity and demonstrate critical thinking skills.