Social media, such as Twitter, have skyrocketed in popularity over the past few years. In fact, social media have been widely used by students and instructors as teaching and learning tools. In response to the increasing use of Twitter in the educational field, we have collected ten studies between 2011 to 2020 in order to assess the relationship between social media, specifically Twitter, and students' engagement and grades. We have conducted a meta-analysis to provide empirical evidence concerning the impact of Twitter on student engagement and achievement. Furthermore, we have utilized the manual approach of content analysis in order to code these articles. Overall, metadata suggests that Twitter has a stronger impact on student engagement than on grades. Nevertheless, its impact is not necessarily positive, especially on grades.