The Science of Reading has the potential to have an enormous impact on historically marginalized groups of students and their ability to read at the same complexity level as their peers. The inability of educators, administrators, and other stake holders to decrease the achievement gap of historically marginalized groups of students makes the need for change even more urgent. In this study, the researcher examined the existing achievement gap (2018-2019) in the two largest urban school districts in Pennsylvania to determine the significance of the gap, specifically within grade 3-5 or 3-8 classrooms. The researcher then examined the curricular materials provided to teachers in these districts from grades K-2 and the materials alignment with the components of the Science of Reading research. Using a post positivism theoretical framework (Creswell & Creswell, 2018), the researcher examined both sets of data simultaneously to draw conclusions about the potential impact of curricular materials on the achievement gap. The researcher found that a statistically significant gap in proficiency existed between students identified as Black or Hispanic and students identified as White or Asian. The researcher also found that the reading curricular documents did contain parts of each component of the science of reading, but that the curriculum did not align with the reading research for each component. [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.]