This study explores students' participation in English for Academic Purposes classrooms from both teachers' and students' perspectives. Data were collected from videotaping of 11 English for academic purposes classes, semi-structured interviews with 12 teachers and stimulated-recall interviews with 33 students. The results indicate that three types of participation were identified, including willing, silent and forced participation. The results also show that a range of contextual and individual factors affect students' participation in class activities and discussions. The contextual factors include class atmosphere, teacher support, peer participation, task, topic and interactional pattern. The individual factors include students' confidence, personality and their perceived and actual communicative competence. Pedagogical implications and directions for future research are also discussed.