In Sri Lanka science education in schools plays a vital role in developing the scientific knowledge and skills that are required for a knowledge-based society. While these knowledge and skills are being developed through educational reforms that promote student-centred learning, there is also an increasing emphasis in Sri Lankan secondary schools on developing independent and autonomous learners. No studies have been found that have examined the practices that Sri Lankan senior secondary school teachers use to develop students' science achievement, nor have there been studies that have examined whether or not these practices are associated with developing student autonomy, in particular, self-regulated learning (SRL). This study aimed to examine these topics. The present study comprised two phases, both of which were qualitative in nature. In Phase 1, the research questions were: (1) What practices do senior secondary school teachers use to foster students' science achievement? and (2) What understandings do the teachers have about the Sri Lankan government's policy related to student-centred learning, student autonomy, and the teacher's role as a facilitator? Focus group interviews were conducted with 12 science teachers from three schools in the Kalutara district of Sri Lanka. Inductive thematic analysis was used to analyse this data. The questions addressed in Phase 2 of the study were: (1) What practices do senior secondary school teachers use to foster students' science achievement? (2) How do senior secondary school teachers use these practices in their science classrooms? and (3) Which of these classroom practices are related to SRL? Using a case study approach, two classroom observations and one semistructured interview were conducted with four teachers. The data were analysed using inductive and deductive thematic analysis. Pintrich and Zusho's (2007) model of student motivation and SRL was used in the deductive analysis. A cross-case analysis was also conducted. Overall, the findings revealed that the senior secondary science teachers used a variety of teaching practices to foster their students' science achievement. These practices related to developing scientific learners (e.g., demonstration, group experiments), developing students' science interests (e.g., "hands-on" learning activities), helping students to achieve their goals (e.g., setting realistic goals and deadlines for meeting goals), developing students' independent learning (e.g., offering "choice" in selecting learning tasks, choosing peers when working on group experiments), and practices to identify and support students (e.g., conducting after-school classes). An analysis of the practices used in Phase 2 revealed that some of the practices could be described as relating to SRL. However, even when the practices could be described as SRL-related practices, the teachers used them infrequently. The SRL-related practices were practices to develop cognition Publications during candidature Conference papers during candidature: