The National Council of Teachers of English (NCTE) has long-established positions on class size for English language arts teachers. Today public schools employ 250,000 fewer people than before the recession of 2008-09, while enrollment has increased by 800,000, and class sizes in many schools are at record highs (Rich, 2013). Research shows that class size matters. In research on early elementary school students, small classes usually mean fewer than 20 students, while for high school students the definition of "small" classes is usually somewhat larger. There are similar variations in what constitutes small classes for college writing instruction. There is a shifting relationship between class size and teacher workload. Reducing class size can, for example, increase teacher workload if the number of students per class is lowered, but teachers are assigned one more class per day. This position statement discusses the following topics in relation to class size and why it matters: (1) Academic Performance; (2) Student Engagement; (3) Long-Term Success; (4) Teacher Retention; and (5) The Cost Factor. Recommendations on how existing research should guide policy decisions conclude the statement.