Purpose: This study investigates the implementation of the Practicum Lesson Study (PLS) model, which is designed to be used by preservice teachers (PSTs), mentor teachers and advisors during school practicum. Design/methodology/approach: Employing a design-based research (DBR) framework and a multiple case study design, the research in this study evaluated the PLS model through eight distinct cases across two phases of research. In both phases, the qualitative research explored the nature of the stages and steps followed in each case, providing detailed descriptions of the procedural arrangements, teaching sessions and discussion meetings. Views of the participants regarding their satisfaction levels towards the PLS model, its benefits and challenges were collected through semi-structured interviews and a questionnaire. Findings: The results of the research highlighted significant benefits of the PLS model, such as self-reflection, peer reflection and collaborative practices. These processes notably enhanced PSTs' abilities to dynamically adjust teaching strategies based on real-time observations and feedback, effectively integrating suggestions from meetings with practical classroom experiences. However, the study also identified several challenges, such as managing diverse opinions and coping with information overload. Research limitations/implications: Based on the comprehensive exploration of the PLS model, the study offers several implications for practitioners and suggestions for future research such as a closer examination of changes in beliefs and identity over time during PLS. Originality/value: The study carries the significance of employing a DBR in the context of implementing LS during ELT school practicum.