For nearly four decades, school finance has become progressively more central in school reform efforts aimed at improving student performance. At the same time, the focus of many school business officials and policymakers has turned to efficient uses of current resources in lieu of uniform increases in school funding. With regard to improving student achievement, class size reduction has become a popular state policy tool, but it remains one of the more costly education reforms, given the need to hire additional teaching personnel and provide additional classrooms. However, if co-teaching were allowed, capital costs associated with new classroom space could be reduced, or even eliminated. Given the popularity of class size reform, costs for implementation, and fiscal concerns of school business officials and policymakers, this article brief reviews the literature on the efficacy of class size reduction, describes the context of Florida's adoption of a Class Size Amendment, and examines the benefits and challenges related to co-teaching instructional strategies. The final section discusses implications for other states considering class size reform. (Contains 38 endnotes.)