Abstract: In the present multilingual world, social network plays a significant role in language development in diversified contexts. This paper introduces the social network analysis (SNA) as both theory and method, and provides a synthesis of the state-of-the-art interdisciplinary research in applied linguistics that has adopted SNA. Moreover, it highlights the methodological designs and exemplifies different types of designs with empirical studies. It concludes by blueprinting future research directions, and calls for multidisciplinary and transdisciplinary collaborations across countries in order to address complex, real-world challenges in language learning and teaching.