This doctoral dissertation investigates the effects of the No Child Left Behind (NCLB) policy on educational equity in New Jersey, focusing on three primary research questions. Firstly, the study examines whether the implementation of NCLB mandates led to the closure of achievement gaps between black and white students, as evidenced by disparities in state assessment scores and National Assessment of Educational Progress (NAEP) scores. Secondly, it explores potential factors contributing to the persistence of achievement gaps, particularly examining differences in opportunities among schools within the state. Lastly, the study investigates the impact of NCLB mandates on instructional practices and student achievement in New Jersey schools. The methodology involved a multi-faceted approach. Firstly, the study examined New Jersey's education policies before and during the implementation of NCLB to provide context for understanding the policy's impact. Secondly, quantitative analysis was conducted by examining state test scores (e.g., NJASK, GEPA, HSPA) for 4th, 8th, and high school students and comparing these scores to NAEP data to identify trends in achievement over time. Additionally, qualitative insights were gathered through interviews with education professionals who were active during the NCLB era, providing valuable perspectives on the implementation of NCLB mandates at the district level. By employing this comprehensive methodology, this dissertation aims to provide a thorough assessment of NCLB's impact on educational equity in New Jersey. The findings of this study have implications for educational policy and practice, informing efforts to address achievement gaps and promote equitable opportunities for all students in the state and beyond. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]