<![CDATA[This study investigates the implementation of a peer teaching model assisted by trainer media to support students' practical competency in engine management system learning in vocational education. The study employed a Classroom Action Research (CAR) design integrated with a mixed-methods approach. The research was conducted through two action cycles consisting of planning, action, observation, and reflection. Quantitative data were obtained from students' practical competency assessments and teacher performance observations, while qualitative data were collected through classroom observations, documentation, and reflection records. The quantitative data were analyzed descriptively by comparing competency achievement and teacher performance across the action cycles, while qualitative data were analyzed thematically with the assistance of NVivo. The results showed a substantial descriptive improvement in students' practical competency. The proportion of students achieving the Competent category increased from 51% in Cycle I to 86% in Cycle II, representing an increase of 35 percentage points and exceeding the predetermined success criterion of ?85%. Teacher performance also increased from 69 in Cycle I to 87 in Cycle II, representing an improvement of 18 points and exceeding the predetermined criterion of ?80%. The qualitative findings indicated that the learning process was characterized by increased peer interaction, practical engagement with trainer media, teacher facilitation, and reflective improvement across the action cycles. The findings suggest that the integration of peer teaching, trainer-supported practical learning, and reflective teacher facilitation provides a coherent pedagogical approach for competency-oriented vocational learning. However, because individual-level data were unavailable for inferential analysis and the study did not employ a comparison group, the findings should be interpreted as context-specific evidence of instructional improvement rather than definitive evidence of causal effectiveness]]>
