Feedback is significant in language learning and teaching. Nevertheless, how feedback is utilised effectively in various instructional approaches and assessment tools remains contentious. In portfolio scholarship, feedback plays a pivotal role in aligning language teaching, learning, and assessment seamlessly. Although feedback has been constantly reported in second language portfolio studies, not much, thus far, has been investigated to understand the role of feedback in both formats, namely paper-based and electronic portfolios (also known as e-Portfolios) in compulsory education. To fill this lacuna, this article discusses what role feedback plays in portfolio assessment; reviews how the feedback process is similar and different in two portfolio mediums; and identifies which portfolio format could facilitate transformative feedback experience throughout portfolio development stages. To achieve these goals, the article first unpacks the role of feedback in language education and its link with formative assessment and self regulated learning. The article goes on to review research on feedback in both portfolio versions in terms of divergences, convergences, and categories. It further discusses six contemporary feedback issues in portfolio assessment. Afterwards, the article evaluates the extent to which portfolio integration in Hong Kong compulsory education promotes or constrains feedback provision and engagement. Lastly, teaching implications of how to maximise the learning-oriented potential of multimedia feedback in portfolio programmes are recommended.