This report describes how teachers support ninth-grade students who are doing scientific investigations in Natural Sciences in South African schools. This is of interest as allowing students to participate in inquiry-based investigations is a significant shift from traditional practices. It presents a new challenge to teachers as it signals an opportunity to shift from a teacher-centred to a student-centred approach in practical inquiry. The research study adopted a mixed methodology research design that involved the collection of both quantitative and qualitative data. The quantitative data were collected by means of questionnaires that were administered to 55 teachers. Qualitative data were collected by means of five classroom observations of student investigations and in-depth teacher interviews. The analysis of all the data revealed that teachers believe in providing support and not allowing learners to discover for themselves when participating in investigations. Teachers use a number of support strategies depending on the stage of the investigation. Based on these findings, a learning progression of teacher support for increasing learner autonomy was formulated which teachers can use in guiding them in the use of appropriate support strategies as they shift students towards greater autonomy in doing investigations.