Students’ low academic performance in high-poverty schools has been a prevalent problem in the United States. Educational leaders have curricular options for underperforming students to make academic gains, particularly in Title I schools. Student performance accountability is part of the Elementary and Secondary Education Act (ESEA) of 1965, which was reauthorized as No Child Left Behind Act of 2001 (NCLB). NCLB mandates stipulate students attain academic proficiency. The purpose of the current quantitative, retrospective, quasi-experimental, static group comparison study was to determine if an increase occurred in reading achievement of 10^th grade students with implementation of a school-wide, interdisciplinary reading literacy plan intended to increase student performance on the state’s high-stakes examination. This study used multi-year, successive 10^th grade cohorts from an urban, public Title I high school in Arizona. Academic achievement data were archived and retrospective from Arizona’s high-stakes, criterion-based examination scores. A two-sample, one-tailed t-test was conducted to find differences in mean value, standard deviation, and variance between two cohorts. Statistical analyses revealed a significant statistical difference on the reading portion of the state’s high-stakes examination scores between cohorts, revealing the control group outperformed the treatment group, thus challenging existing results from successful school-wide literacy plans in public Title I schools. Results indicated implementation of a school-wide, interdisciplinary reading literacy plan does not increase achievement for students on the reading portion of the state’s high-stakes examination at a Title I urban high school in Arizona.