Many educators have suggested the usage of peer assessment for the improvement of learning outcomes. Peer assessment facilitated by Internet technology can enhance anonymity and lead to better interactions between students and peer reviewers. In addition, online peer assessment can effectively store students’ peer interactions and learning progression portfolios for further analyses or evaluations. However, most peer assessment studies have been conducted with higher education students, such as college or graduate students. This chapter reports an initial meta-analysis of a series of research utilizing online peer assessment involving Taiwanese high school students. This study also summarizes some practical principles for conducting online peer assessment in high school settings. Finally, this chapter proposes the required literacy of using Internet-based peer assessment, both for the learners and teachers.