Most states nationwide have had policies for several decades that limit the number of students assigned to public K-12 classrooms. Southern Regional Education Board (SREB) states, led by Tennessee and Texas, spearheaded this effort in the 1980s, and SREB's own "Legislative Briefings" have marked the growth of class-size policies across the region. The policies became more popular in the 1990s, following Tennessee's now-famous Student/Teacher Achievement Ratio (Project STAR) experiment. Today, every SREB state has some kind of policy that controls class size. Supporters argue that smaller classes help raise student achievement, especially in the elementary grades. Critics, on the other hand, argue that the increases are not sufficient to justify the overall state cost. This argument has gained greater support since the economic downturn began in 2007. As a consequence, policy-makers and education leaders in some states have sought to relax class-size limits in an effort to cut state and local education costs. While the public largely has supported the limits up to now, the mood may be shifting. A 2011 Gallup poll found that when given a choice between "smaller classes with average-performing teachers" and "larger classes with better-than-average teachers," the public overwhelmingly chose better teachers over smaller classes. Policy-makers and education leaders in some SREB states may be considering changes to their class-size policies but want to do so without jeopardizing student achievement. This "SREB Policy Brief" summarizes current policies (often referred to as "class-size reduction policies") across the region, reviews prominent research on the issue, and offers recommendations on how states might make sensible adjustments. (Contains 2 figures.) [This brief was written with Matthew Lenard.]