The Lucy Calkins' Reading Units of Study is a literacy curriculum for students in grades K-8. The curriculum has proven to be advantageous for elementary students who have strong reading skills and a broad vocabulary. However, some scholars argue that the curriculum does not meet the needs of students who lack a strong foundation in reading. What was not known is whether similar concerns present themselves at the middle school level. The problem this study addressed is the disparity in reading achievement between White and Black middle school students. The purpose of this mixed-methods study was to determine if the Reading Units of Study curriculum aids in closing the reading achievement gap between White and Black 6th, 7th, and 8th grade students. Student assessment scores were gathered from the 2020-2021 and 2021-2022 school years and analyzed using statistical tests. A questionnaire was used to identify English Language Arts teachers' perceived benefits and drawbacks of using the curriculum to close the reading achievement gap between White and Black students. The results of the study suggested that the use of the curriculum has no statistical impact on closing the reading achievement gap between White and Black students as measured by the Northwest Evaluation Association (NWEA) assessment nor the Missouri Assessment Program (MAP) assessment. Qualitative data from teachers were gathered and coded into themes. Four themes that emerged from the data were critical thinking, stamina, choice and diversity, and student response. Qualitative findings supported the quantitative findings and revealed that teachers' perceptions of using the curriculum to close the achievement gap was not favorable. Suggestions for future studies include using more quantitative data points, gathering perception data from multiple stakeholders, evaluating curriculum fidelity, replicating the study at the elementary level, and comparing different curricula resources' impact on closing the achievement gap. [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.]