The authors of the No Child Left Behind Act of 2001 anticipated that a majority of school districts or schools would not be able to attain state and national achievement standards without assistance. Consequently, the Act created a major tenet known as Supplemental Educational Services (SES) programs to improve the learning outcomes of students placed 'at-risk' and to hold public schools accountable for increasing the proficiency levels of students in reading and mathematics. This study examined whether provision of supplemental educational services significantly improved academic achievement of students in Baltimore City Public Schools after they received supplemental services. A quasi-experimental research design was utilized in this study to compare SES participants and non-participants. Keywords: supplemental educational services, adequate yearly progress, Maryland State Assessment School districts have attempted to meet the terms of the No Child Left Behind Act of 2001 (NCLB, 2001). The mandate requires that districts provide Supplemental Educational Services (SES) to improve academic performance and close the achievement gap for low income minority children. This is especially important for minority students living in urban communities and enrolled in Title I schools. The authors of NCLB anticipated that a majority of school districts or schools would not be able to attain state and national achievement standards without assistance. Consequently, the Act created SES programs to improve the learning outcomes of at-risk students and to hold public schools accountable for improving the proficiency of students in reading and mathematics. Those SES programs refer to tutoring outside of the regular school day for low-income and minority children that are in Title I schools. Tutoring normally begins in December and usually last for three months. However, some students are wait listed and may not receive SES until after the state examination. Although SES programs exist in virtually every school district in the U.S., policymakers and school districts are apprehensive about using SES programs to close the achievement gap. This is especially important for the nation's 48 million children from high-poverty school districts in Title I Schools (U.S. Department of Education, 2003). Lacking hard data, officials are skeptical about SES programs improving the academic proficiency of students and reducing the number of poor-performing schools not meeting adequate yearly progress (AYP) as required by NCLB. Similar to other urban school districts, the Baltimore City Public Schools System (BCPS) faced challenges more extreme than most school districts. For example, the school district experienced high leadership turnover; there have been three superintendents since 2003. Of the 91,738 students in BCPS in 2003, 90% were minority students who consistently scored low on standardized tests (MD State Department of Education, MSDE, 2003). 2003, BCPS was the first complete school district in Maryland classified as In Corrective Action (White, 2003a, 2003b). the same year, BCPS had the highest percentage of schools in Maryland that failed to make AYP: Eighty-four of 183 schools were identified as chronically low-performing (Grasmick, 2003). Simultaneously, BCPS faced a $58 million deficit, a $52 million cash-flow shortfall, and a mandate to relinquish financial control in order to receive a $42 million advance from the governor (Donovan & White, 2004; Olesker, 2004). Additionally, BCPS was charged with mismanaging federal Title I funds that were targeted to improve the academic performance of students enrolled in high-poverty schools. Subsequently, under NCLB guidelines, BCPS developed and implemented plans to eliminate Maryland State Department of Education sanctions. Plans included the full implementation of SES. For the next five years, BCPS delivered SES to approximately 10,000 minority students who were not meeting criteria in schools that failed to achieve AYP. …