The metaverse has the potential to revolutionise education in several ways. It can provide students with immersive learning experiences, allowing them to explore and interact with virtual worlds and objects that are difficult or impossible to replicate in the real world. Yet, studies investigating the impact of the metaverse on students' skills and performance are limited due to its novelty. The key objective of the current research is to unveil the overall effect size of integrating metaverse technologies into educational contexts and the significance of several factors that could influence the effectiveness of such technology on the learning ecosystem. The research as adopted the quantitative research methodology to address the research questions, which focused on following the principles of meta-analysis with calculating the effect size of relevant studies, by mainly using PRISMA. It an evidence-based minimum set of items for reporting in systematic reviews and meta-analyses. Accordingly, twenty-four experimental studies conducted between 2020-2023 were statistically analysed. The results have explicitly that employing the metaverse generally has a large effect size (d=0.94) on learning, indicating that integrating the metaverse in educational settings can significantly enhance students' performance. Other variables, such as educational level, skills targeted, subject taught and technology used, were also investigated. A discussion of these findings and their implications are presented.