A person’s belief in their ability to succeed in a particular situation – their self-efficacy – has a strong impact on their behaviour. As a result, understanding self-efficacy is a key component when interpreting achievement results. In the pursuit of improving South African learners’ achievement in science, Sylvia Hannan and Andrea Juan explore science self-efficacy using the 2019 Trends in International Mathematics and Science Study (TIMSS). They argue that enhancing learners’ self-efficacy is an important piece of the achievement puzzle, as well as a desirable outcome in itself.