Large classes are the norm and a cause for concern for many language teachers. In
many, if not most, educational contexts around the world, classes of 40, 50 or even more
students are common. Teachers appear to believe that such class sizes are the cause of many
of the problems they face. Yet, while large classes may add substantially to teacher workload,
there is almost no evidence from English language teaching contexts that large class sizes
adversely affect learning. This paper investigates the impact of class size on student learning
in the context of a Thai university