This book presents mixed-methods research into Chinese students' willingness to communicate (WTC) in an EFL classroom context. The interrelationships between WTC and motivation, communication confidence, learner beliefs and classroom environment are examined using structural equation modelling on data collected in a large-scale survey. These results are then complemented and expanded upon in a follow-up multiple case-study that identifies six themes which account for fluctuations of WTC over time and across situations. The qualitative and quantitative data provide the grounds for the proposition of an ecological model of WTC in the Chinese EFL university classroom, which reveals that WTC is socioculturally constructed as a function of the interaction of individual and environmental factors inside and beyond the classroom walls.