The purpose of this study was to determine the impact of the Core Knowledge Language Arts (CKLA) program as implemented by ABC District on pre-kindergarten students' Early Screening Inventory (ESI) academic assessment scores and kindergarten through second-grade students' Northwest Evaluation Association-Measure of Academic Progress (NWEA-MAP) literacy assessment scores for the 2016-2017 and 2017-2018 school years. Students' achievement scores were compared within grade-levels and within subgroups. To further test the CKLA program's impact, researchers examined the growth of student academic assessment scores within a school year and over the span of two consecutive school years (2016-2017; 2017-2018). Researchers also sought to identify perceptions related to the CKLA program held by participating parents, teachers, and administrators. Participants included 2,341 students, 147 parents, and 50 educators. The researchers implemented a predominately quantitative mixed-methods design to collect data. Perceptions of the CKLA program held by parents and educators were collected using questionnaires and teacher interviews. Findings led researchers to conclude that there were no statistically significant differences in achievement test scores for the majority of the CKLA taught students when compared with non-CKLA taught students. However, statistically significant differences in assessment scores were found between CKLA-taught and non-CKLA taught pre-kindergarten students, male students, and SWD. The findings also revealed no statistically significant differences between the growth scores of CKLA taught students and non-CKLA taught students. Nevertheless, the majority of participating parents, teachers, and administrators held positive perceptions of the CKLA program and its potential for improving literacy. [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.]