Background: Data literacy (DL) is vital for teachers, as it enables them to build on data and improve teaching and learning. Therefore, developing DL among pre-service teachers is critical. Objectives: The purpose of this study is threefold: to evaluate whether a feedback visualisation of peer assessment-based teaching approach (FVPA-based teaching approach) can (1) promote pre-service teachers' DL; (2) enhance their learning motivation; and (3) improve their cognitive load. Methods: The research was conducted based on a pre-test-post-test control group quasi-experimental design. With 20 participants in the experimental group and 21 in the control group, a total of 41 pre-service teachers were included in the study. The pre-service teachers in the experimental group adopted the FVPA-based teaching approach, and those in the control group adopted the traditional peer assessment-based learning approach. Results and Conclusions: The experimental group participants outperformed the control group participants in DL, learning motivation, and cognitive load. FVPA was conducive to helping pre-service teachers critically interpret data, understand their teaching and learning issues, and improve self-reflection. The findings indicate a reciprocal relationship between learning motivation and DL; improving the learning motivation of pre-service teachers could promote their DL. Implications: This study contributes to current knowledge by providing empirical evidence on the benefits of an FVPA-based teaching approach in improving pre-service teachers' DL, motivation, and cognitive load. The study findings, limitations, and prospects for future research are discussed.