There is limited evidence on what drives teachers to change their teaching practices. Using primary qualitative data from 78 Zambian education personnel from the school to provincial level, we combine thematic analysis with unsupervised machine learning to identify drivers of pedagogical shifts. We then combine qualitative analyses with linear probability models to uncover their associations with teacher professional development. Our findings suggest that teaching practices are malleable, with change being predominantly driven by on-site continuous professional development (CPD) opportunities relating to team-based problem-solving, verbal discussions, and skills acquisition. Taken together, this study highlights the potential of school-based CPD opportunities as means to alter teaching practices, in a developing-country setting.