<p dir="ltr">The purpose of this three-paper dissertation is to examine the effect of the Community of Inquiry (CoI) framework-informed use of social media on language learning through a meta-analysis and two mixed-method studies. The first paper is a meta-analysis that examines the overall effect of social media use on language learning and the factors that moderate the effect. The second paper is a mixed-method study to investigate the effect of the Community of Inquiry-informed use of Facebook discussion activities on English speaking. The third paper is a mixed-method study to examine the effect of the Community of Inquiry-informed use of Facebook discussion activities on English writing. The combined results expanded our understanding of the overall effect of the use of social media on language learning and the applicability of the CoI framework in social media platforms. Finally, the last chapter synthesized the findings across three papers and presented implications for research and practice. </p><p><br></p>