Teaching large classes is always seen as problematic by the teachers. In most of the cases it is found that the teachers do not feel comfortable to provide opportunities to the learners in large ESL classes because of fear of losing control over students. This study reveals the attempt made to promote interaction among students in large ESL classes in the government school classes of Karachi, Pakistan. The study engaged a class of 49 students of grade four. The study was conducted as action research. Additional data was collected through participant observation and reflection. The English language teacher of the class in which the study was conducted was involved as a critical friend for the observation and reflection of the classroom teaching. Interviews with the teacher were conducted at the beginning and end of the study to understand the teacher's beliefs and attitude towards interaction in large ESL classes. Finally, learners were interviewed to find out their perception about the same. The study reveals the challenges I faced while promoting interaction in large ESL classes. It also indicates the strategies I tried out to overcome the challenges. Furthermore, it shows how teachers and learners in large ESL classes perceive promoting interaction among students. The study also highlights the factors that facilitate interaction among students in large ESL classes. Finally recommendations and implications are made for the teachers, teacher educators, and the school context.