We model how class size affects the grade higher education students earn and we test the model using an ordinal logit with and without fixed effect on over 760,000 undergraduate observations from a northeastern public university. We find that class size negatively affects grades for a variety of specifications and subsets of the data, as well as for the whole population. Average grade point declines as class size increases, precipitously up to class sizes of twenty, and more gradually but monotonically through larger class sizes. Evidence suggests that this phenomena is not exclusively caused by a “small-class” effect.