School leaders face increased pressure to identify instructional and administrative practices that increase student achievement. However, achievement gaps persist between disadvantaged and non-disadvantaged student groups. This study highlighted relationships between ability grouping and academic achievement in a suburban school district. Thorndike's social intelligence framework proffered learning as a social process and provided a theoretical framework. Research questions addressed whether ability grouping impacted academic achievement of students with special needs, English language learners, and the economically disadvantaged based upon Grade 5 Pennsylvania System of School Assessment mathematics data, Grade 5 mathematics 4Sight data, and Grade 5 enVisionMATH benchmark data. Four independent-samples t tests, 3 chi-square analyses, and 2 point-biserial correlation analyses determined statistically significant differences between student achievement and class placement and rejected 4 of 9 null hypotheses. The current study resulted in a project in the form of a white paper. The white paper included an overview of ability grouping and district assessment data, and recommended a district discussion around ability grouping and alternate grouping structures targeted at increasing student achievement. Implications for local and broader social change included potential elimination of ability grouping for mathematics instruction; reduced inequity of educational opportunities; and decreased achievement gaps between students with special needs, English language learners, and students who are economically disadvantaged compared to students not in these groups. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]