This paper is devoted to the study of the impact of class size on teaching and learning English as a foreign language. The investigation was conducted at the department of English at Abdelhamid Ibn Badis University. The department has witnessed a huge increase in the enrolment figure in the past decade which resulted into an increase in class sizes. This has created problems for staff and students alike. Despite the steps taken by the administrators to reduce the number of students, the problem of class crowding still persists. The department of English, alone, has an enrolment of almost 3000 students, it is a huge number indeed if we take into consideration the availability of facilities and resources. The aim of this study is to explore the organizational and pedagogical difficulties that are frequently encountered by the teachers dealing with large classes and the effects on student learning. Additionally, this paper proposes some suggestions on how to deal with class overcrowding. As part of our research, we have given questionnaires to 200 students and 40 teachers. The findings of the survey clearly demonstrate that large class sizes have an adverse impact on the quality of teaching and learning.