The purpose of this study was to examine the extent to which high school scheduling affects students' academic achievement, attendance, and disciplinary incidents. The study compared 2009-2013 data from high schools utilizing the A/B block schedule and high schools using a traditional schedule in a mid-Atlantic state. This study used quantitative methods to describe, analyze, and interpret algebra, biology, and English HSA scores as well as attendance rates and disciplinary incidents from 2009-2013. Correlation coefficients and independent t-tests were conducted to analyze the difference between the two schedule designs with respect to three achievement indicators: algebra, biology and English HSA scores. The findings yielded the following conclusions: (a) students experienced higher algebra scores on the A/B traditional schedule than the block schedule only in the year 2009; (b) students experienced higher biology scores on the traditional schedule than the A/B block schedule in all five years; (c) students experienced higher English scores on the traditional schedule than the A/B block schedule only in 2010; (d) student attendance rates were similar for high schools that use A/B block schedule and those that use the traditional schedule; (e) disciplinary incidents decreased more for students under the traditional schedule than students under the A/B block schedule in the years 2011 and 2013. Recommendations for research included: recruitment and retention of quality teachers, examine the relationship between school schedules and biology courses, and research additional factors, such as FARMS, socioeconomic, urban/suburban students that may play a significant role in student academic achievement. Recommendations for policy/practice included: utilization of the traditional schedule for biology classes, using part of the teacher evaluation to monitor progress and academic achievement, and to look at students' perceptions and performances in middle and high schools. This should also include teachers' and parents perceptions.