The purpose of this study is to investigate physics teachers’ (TPCK) and their learners’ achievement in electricity. A purposive sample of 42 Grade 11 physics teachers and 1423 learners participated in the study. An explanatory mixed method research design was employed in the study to collect data. A survey questionnaire (PTTPCKQ), consisting of six-point Likert scale questions, was answered by participating teachers. Similarly, their learners responded to a confirmatory questionnaire (LCPTTPCKQ). The learners also responded to the Electricity Learning Confirmatory Questionnaire (LELCQ) and wrote an achievement test called Learner Electricity Achievement Test (LEAT). The data collected was analysed both quantitatively and qualitatively. Quantitatively, it was found that a positive, statistically significant relationship existed between physics teachers’ experience and their learners’ achievement [Spearman’s rho (42) = .39, p = .011] as well as physics teachers’ TPCK and their qualifications [Spearman’s rho (42) = .33, p = .003]. There was also a positive statistical relationship between physics teachers’ TPCK and learner achievement, yet this was not statistically significant. There were positive, statistically significant relationships between all the constructs of the physics teachers’ TPCK and their TPCK from the analysis of the PTTPCKQ. There were positive statistically significant relationships between all the constructs of the physics teachers’ TPCK and their TPCK, according to the analysis of the LCPTTPCKQ. Furthermore, comparing the learners’ responses on the LCTTPCKQ and their teachers’ responses on the PTTPCKQ, it was found that both learners and teachers provided similar responses for all the constructs of TPCK except TCK. Qualitative data analysis further revealed that the technologies used by these teachers were PhET Simulations, YouTube Videos, Power Point Presentations, Interactive White Boards, and Mindset Videos. Finally, between 12.9% and 5.2% of the learners reported that their teachers had neglected to teach some sections of the electricity in the curriculum. / Mathematical Sciences / Ph. D. (Mathematics, Science and Technology Education)