This Element provides readers with a detailed overview of the social factors that affect second language (L2) phonology acquisition and use. Through a state-of-the art synthesis of the relevant literature, this Element addresses the following questions: What do we mean by social factors? Which social factors have been investigated in research on L2 phonological acquisition and use? How and why do social factors affect L2 phonological acquisition (production and perception) and use? What are the implications of the social factor findings for teaching L2 pronunciation? The Element answers these questions through a synthesis of key findings in research on social factors and L2 phonology. Conclusions and implications for teaching, as well as key readings and references, follow the research synthesis.