This book explores how international students construct target language- (TL-) mediated social spaces for socializing. The author asks what factors either prevent or promote the construction of TL-mediated socializing opportunities by international students, how such students can grow both as TL learners/speakers/users and as people throughout their TL-mediated socializing, and how international students' socializing, and their affective states during socializing, change across time during their stay in the host country. He analyses international students' TL-mediated socializing and its co-construction primarily within the conceptual frameworks of situated learning (Lave & Wenger, 1991) and affinity space (Gee, 2004), with additional insights from peripheral/marginal participation (Wenger, 1998), scaffolding (Wood, Bruner, & Ross, 1976), identity (re-)construction (Norton, 2000), and Discourse (Gee, 2012). This book proposes concrete educational and pedagogical implications, based on the findings, which will be meaningful for both educational institutions and educators involved in study abroad programs or education. It will also be of interest to students and scholars in related academic fields including Applied Linguistics, Language Education, Sociolinguistics and Pragmatics.