The objectives of this study are: (1) to reveal how the pre-service EFL teachers’ understanding of formative assessment; (2) to reveal how the pre-service EFL teachers implemented formative assessment. The study took place in one of the universities in Surakarta. The participants of this study were three pre-service EFL teachers who taught in vocational school during the internship program. Additionally, the participants already attended an English Language Teaching Management (ELTM) course, Language Teaching Evaluation (LTE), Micro Teaching, Best Practice course, and internship in the seventh semester. This study employed the biographical narrative inquiry method and the data gathered through narrative frame, interview, and artefacts. The study explored the pre-service EFL teachers’ experiences and knowledge in implementing formative assessment during their internship program. The findings of the study revealed that the participants have great understanding of formative assessment. It is because the participants had adequate comprehension of formative assessment, they also could explain detail information of formative assessment, and they have good experiences of implementing formative assessment in the internship. They were also implemented formative assessment systematically. However, they still need several areas of improvement such as they need improvement in increasing motivation and delivering the feedback to the students.
